**Barley Genetics Newsletter (2005) 35:3-8**

![](media/image1.jpeg){width="4.5625in" height="0.4270833333333333in"}

**Barley mutants with short roots**

Malgorzata Nawrot, Iwona Szarejko and Miroslaw Maluszynski

Department of Genetics, University of Silesia,\
Jagiellonska 28, 40-032 Katowice, Poland

e-mail: <mnawrot@us.edu.pl>

**Abstract**

Nine mutants showing significant shortening of seminal roots have been
identified in the collection of dwarf and semi-dwarf forms obtained
after mutagenic treatments of spring barley varieties with
N-nitroso-N-methylurea and sodium azide. Genetic analysis, performed at
the seedling and the spike-emergence stage of plant development,
indicated that a single recessive gene was responsible for root
shortening in each of analyzed mutants. One short-root mutant developed
also very short root hairs. Short roots and short root hairs were
controlled by separate genes. The reciprocal crosses of four mutants
revealed that they were non allelic.

**Introduction**

Roots play a decisive role in plant growth and development. The
mutational analysis of root system provides a useful tool for revealing
the genetic basis of root characters, such as root apical organization,
root cell proliferation, secondary root formation, root hair
development, and root elongation. The most advanced results on genetics
of root system development and morphology were achieved in a model plant
species *Arabidopsis thaliana*, where several root mutants have been
described (Baskin et al., 1992; Benfey et al., 1993; Aeschbacher et al,
1994; Baskin et al, 1995; Hauser et al., 1995; Di Laurenzo et al.,
1996). In agronomically important crop plants, only a few root system
mutants are known (Yao et al., 2003; 2002; Inukai et al., 2001;
Tsyganov, 2000; Tsuchiya, 1974). In the presented paper we report on
barley mutants characterized by seminal roots significantly shorter than
roots of parent varieties during whole vegetation period.

**Material and methods**

The studies included nine dwarf and semi-dwarf (sd) spring barley
mutants developing shorter seminal roots than parent varieties. The
mutants, obtained after mutagenic treatment with N-nitroso-N-methylurea
(MNH=MNU), were identified in the collection of dwarf and semi-dwarf
forms of the Department of Genetics, University of Silesia, Poland.
Additionally, one genotype (225DV from cv. 'Diva') developed also very
short root hairs.

Root length at the early developmental stage (8-day old seedling) was
evaluated using a paper roller method. The method based on growing
seedlings in rollers made of filter paper wrapped tightly around a glass
tube (φ 2.5 cm). The plastic-coated wires were enclosed between each
layer of paper, and the surface of rollers was covered with black foil.
Sterilized and pre-germinated seeds (with coleorhiza emerged by 1-2 mm)
were placed embryo down, one beside each of two sides of a wire. The
rollers were placed in containers with equal level of distilled water
and kept in a growth chamber under controlled conditions: illumination
180 µEm^-2^s^-1^, 16/8h photoperiod and temperature 24/22^o^C day and
night, respectively. At the stage of 8-day old seedling, the length of
the longest seminal root and the length of the first leaf were measured.
Three replications of each mutant and its parent variety (10 seedlings
per replication) were included in each analysis.

The second analysis of root growth was performed at 6-week stage. Plants
were grown in the PVC tubes, 125 cm long and 7.5 cm in diameter, filled
with sand. To facilitate the extraction of intact roots, plastic foil
was used to line the inside of each tube. Pre-germinated seeds were sown
into the tubes, and covered with 2-3 cm layer of soil. The experiments
were conducted in a glasshouse, under semi-controlled conditions:
illumination 200 µEm^-2^s^-1^, 16/8h photoperiod and temperature
25/15^o^C day and night, respectively. Every two days, plants were
nourished with 100 ml of ½ MS mineral medium (Murashige and Skoog,
1962). The excess of solution flew out freely from the tubes. Plants
were gently sprinkled with tap water throughout to prevent desiccation.
The experiments were performed in three replications with 3-5 plants per
replication. Plants were harvested and washed after 6 weeks and the
length of the longest seminal root, and the number of roots was
measured.

The analysis of F~1~ and F~2~ generation of the crosses between mutants
and their parent varieties as well as among selected mutants was
performed at the seedling stage. Ten to 20 F~1~ plants and 100-200 F~2~
plants were examined for the longest root and the first leaf length.

**Results**

The selected sd mutants developed significantly shorter seminal roots at
both analyzed stages of plant development (Table 1). Mutant 225DV from
variety \'Diva\' presented the highest level of root and shoot
reduction, with root length reaching only about 40% of parent variety at
the seedling and 50% at the spike-emergence stage. The root length
reduction observed in mutants from variety \'Aramir\' ranged from 25% -
48% at both analyzed stages. The results obtained for four mutants from
variety \'Delisa\' indicated similar level of root length reduction. In
most mutants, the shoot length was slightly more reduced at the seedling
stage than at maturity.

Table 1. Analysis of root and shoot length in mutants and their parent
varieties at the seedling and spike-emergence stage.

+------+------+-------+-----+-------+------+-------+-----+-------+
| Geno | Seed |       |     |       | S    |       | Ma  |       |
| type | ling |       |     |       | pike |       | tur |       |
|      | s    |       |     |       | e    |       | ity |       |
|      | tage |       |     |       | merg |       |     |       |
|      |      |       |     |       | ence |       |     |       |
|      |      |       |     |       | s    |       |     |       |
|      |      |       |     |       | tage |       |     |       |
+------+------+-------+-----+-------+------+-------+-----+-------+
|      | Root | Redu  | Fi  | Redu  | Root | Redu  | Sh  | Redu  |
|      | le   | ction | rst | ction | le   | ction | oot | ction |
|      | ngth | (%)   | l   | (%)   | ngth | (%)   | len | (%)   |
|      |      |       | eaf |       |      |       | gth |       |
|      | \(   |       | len |       | \(   |       | (   |       |
|      | cm\) |       | gth |       | cm\) |       | cm) |       |
|      |      |       | (   |       |      |       |     |       |
|      | \_   |       | cm) |       |     |       | x  |       |
|      |      |       |     |       |      |       | ±   |       |
|      | x ±  |       | x  |       | x ±  |       | SD  |       |
|      | SD   |       | ±   |       | SD   |       |     |       |
|      |      |       | SD  |       |      |       |     |       |
+------+------+-------+-----+-------+------+-------+-----+-------+
| Ar   | 3    |       | 15  |       | 132. |       | 80  |       |
| amir | 2.0± |       | .1± |       | 6±3. |       | .4± |       |
|      | 0.7^ |       | 0.3 |       | 2^A^ |       | 4.5 |       |
|      | A\*^ |       | ^A^ |       |      |       | ^A^ |       |
+------+------+-------+-----+-------+------+-------+-----+-------+
| 0    | 19.  | 38.1  | 12  | 14.5  | 98.  | 25.4  | 56. | 29.6  |
| 14AR | 8±0. |       | .9± |       | 9±5. |       | 6±0 |       |
|      | 2^B^ |       | 0.4 |       | 3^B^ |       | .4^ |       |
|      |      |       | ^B^ |       |      |       | BC^ |       |
+------+------+-------+-----+-------+------+-------+-----+-------+
| 0    | 23.  | 25.3  | 10  | 33.1  | 92.  | 29.9  | 45  | 43.6  |
| 35AR | 9±1. |       | .1± |       | 9±0. |       | .3± |       |
|      | 4^B^ |       | 0.4 |       | 4^B^ |       | 3.1 |       |
|      |      |       | ^B^ |       |      |       | ^D^ |       |
+------+------+-------+-----+-------+------+-------+-----+-------+
| 0    | 16.  | 47.8  | 8   | 42.4  | 80.  | 39.1  | 46  | 41.8  |
| 37AR | 7±1. |       | .7± |       | 8±4. |       | .8± |       |
|      | 6^B^ |       | 0.4 |       | 2^C^ |       | 0.6 |       |
|      |      |       | ^C^ |       |      |       | ^D^ |       |
+------+------+-------+-----+-------+------+-------+-----+-------+
| 0    | 20.  | 36.9  | 12  | 14.6  | 99.  | 24.7  | 61  | 23.6  |
| 90AR | 2±0. |       | .9± |       | 8±4. |       | .4± |       |
|      | 8^B^ |       | 0.5 |       | 8^B^ |       | 1.4 |       |
|      |      |       | ^B^ |       |      |       | ^B^ |       |
+------+------+-------+-----+-------+------+-------+-----+-------+
| Diva | 31.  |       | 14  |       | 136. |       | 85  |       |
|      | 9±3. |       | .7± |       | 0±3. |       | .5± |       |
|      | 7^A^ |       | 1.0 |       | 3^A^ |       | 1.3 |       |
|      |      |       | ^A^ |       |      |       | ^A^ |       |
+------+------+-------+-----+-------+------+-------+-----+-------+
| 2    | 11.  | 63.0  | 5   | 61.9  | 66.  | 51.0  | 41  | 52.0  |
| 25DV | 8±0. |       | .6± |       | 6±2. |       | .0± |       |
|      | 5^B^ |       | 0.4 |       | 2^B^ |       | 1.1 |       |
|      |      |       | ^B^ |       |      |       | ^B^ |       |
+------+------+-------+-----+-------+------+-------+-----+-------+
| De   | 27.  |       | 13  |       | 128. |       | 86  |       |
| lisa | 0±2. |       | .3± |       | 2±2. |       | .3± |       |
|      | 2^A^ |       | 0.2 |       | 3^A^ |       | 5.4 |       |
|      |      |       | ^A^ |       |      |       | ^A^ |       |
+------+------+-------+-----+-------+------+-------+-----+-------+
| 5    | 15.  | 42.6  | 7   | 59.4  | 80.  | 37.1  | 58  | 31.8  |
| 22DK | 5±0. |       | .9± |       | 6±5. |       | .9± |       |
|      | 1^B^ |       | 0.4 |       | 2^B^ |       | 2.0 |       |
|      |      |       | ^B^ |       |      |       | ^C^ |       |
+------+------+-------+-----+-------+------+-------+-----+-------+
| 5    | 16.  | 37.4  | 7   | 59.4  | 88.  | 30.9  | 66  | 23.1  |
| 38DK | 9±0. |       | .9± |       | 6±2. |       | .3± |       |
|      | 6^B^ |       | 0.3 |       | 7^B^ |       | 2.1 |       |
|      |      |       | ^B^ |       |      |       | ^B^ |       |
+------+------+-------+-----+-------+------+-------+-----+-------+
| 5    | 16.  | 40.4  | 7   | 47.4  | 87.  | 32.0  | 65  | 24.1  |
| 87DK | 1±1. |       | .0± |       | 1±2. |       | .5± |       |
|      | 3^B^ |       | 0.9 |       | 5^B^ |       | 3.4 |       |
|      |      |       | ^B^ |       |      |       | ^B^ |       |
+------+------+-------+-----+-------+------+-------+-----+-------+
| 5    | 15.  | 41.1  | 7   | 47.4  | 95.  | 25.4  | 66. | 22.8  |
| 88DK | 9±1. |       | .0± |       | 6±2. |       | 6±0 |       |
|      | 3^B^ |       | 0.4 |       | 3^B^ |       | .7B |       |
|      |      |       | ^B^ |       |      |       |     |       |
+------+------+-------+-----+-------+------+-------+-----+-------+

\* - the same letter for the group of the mutant and parent variety
indicates not significant difference for P=0.05.

Analysis of seminal root length in the F~1~ generation of the crosses
'mutant x parent variety' revealed the recessive character of root
phenotypes in all examined mutants. The segregation of F~2~ progeny
indicated that short seminal roots were recessive and monogenically
inherited (Tab. 2). The allelism test performed up to now for 4 mutants
crossed to each other revealed four different loci responsible for the
seminal root shortening. The allelism analysis of other mutants is in
progress. Short roots and short root hairs of mutant 225DV from variety
Diva were controlled by two separate but linked genes (Tab. 3).

+-----------------+--------+----------+----------+----------+--------+
| Table 2.        |        |          |          |          |        |
| Analysis of     |        |          |          |          |        |
| F~1~ and F~2~   |        |          |          |          |        |
| generation of   |        |          |          |          |        |
| the crosses     |        |          |          |          |        |
| 'mutant x       |        |          |          |          |        |
| parent variety  |        |          |          |          |        |
| and 'mutant x   |        |          |          |          |        |
| mutant'.        |        |          |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| Genotype        | No. of | Seminal  | No. of   |          | χ^2    |
|                 | an     | root     | F~2~     |          | ^~3:1~ |
|                 | alyzed | length   | plants   |          |        |
|                 | plants | (cm)     | with the |          |        |
|                 |        |          | p        |          |        |
|                 |        | x ± SD  | henotype |          |        |
|                 |        |          | of       |          |        |
+-----------------+--------+----------+----------+----------+--------+
|                 |        |          | parent   | mutant   |        |
|                 |        |          | variety  |          |        |
+-----------------+--------+----------+----------+----------+--------+
| Aramir          | 30     | 24.5±    |          |          |        |
|                 |        | 2.0^A\*^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| 014AR           | 30     | 18.      |          |          |        |
|                 |        | 7±1.8^B^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| F~1~ 014AR x    | 17     | 23.      |          |          |        |
| Aramir          |        | 0±0.7^A^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| F~2~ 014AR x    | 97     |          | 69       | 28       | 0.76   |
| Aramir          |        |          |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| Aramir          | 30     | 28.      |          |          |        |
|                 |        | 9±0.1^A^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| 035AR           | 30     | 18.      |          |          |        |
|                 |        | 9±0.5^B^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| F~1~ 035AR x    | 28     | 27.      |          |          |        |
| Aramir          |        | 7±1.3^A^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| F~2~ 035AR x    | 109    |          | 109      | 36       | 0.002  |
| Aramir          |        |          |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| Aramir          | 30     | 24.      |          |          |        |
|                 |        | 5±2.0^A^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| 037AR           | 30     | 12.      |          |          |        |
|                 |        | 9±0.5^B^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| F~1~ 037AR x    | 11     | 23.      |          |          |        |
| Aramir          |        | 3±1.7^A^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| F~2~ 037AR x    | 90     |          | 65       | 25       | 0.36   |
| Aramir          |        |          |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| Aramir          | 30     | 24.      |          |          |        |
|                 |        | 5±2.0^A^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| 090AR           | 30     | 13.      |          |          |        |
|                 |        | 9±0.7^B^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| F~1~ 090AR x    | 13     | 24.      |          |          |        |
| Aramir          |        | 9±1.2^A^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| F~2~ 090AR x    | 85     |          | 63       | 22       | 0.01   |
| Aramir          |        |          |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| Diva            | 30     | 27.      |          |          |        |
|                 |        | 9±0.7^A^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| 225DV           | 30     | 7.       |          |          |        |
|                 |        | 0±0.8^B^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| F~1~ 225DV x    | 27     | 26.      |          |          |        |
| Diva            |        | 5±0.9^A^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| F~2~ 225DV x    | 187    |          | 134      | 53       | 1.11   |
| Diva            |        |          |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| Delisa          | 30     | 19.      |          |          |        |
|                 |        | 6±0.7^A^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| 522DK           | 30     | 11.      |          |          |        |
|                 |        | 8±0.2^B^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| F~1~ 522DK x    | 11     | 21.      |          |          |        |
| Delisa          |        | 8±1.1^A^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| F~2~ 522DK x    | 122    |          | 85       | 37       | 1.84   |
| Delisa          |        |          |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| Delisa          | 30     | 19.      |          |          |        |
|                 |        | 6±0.7^A^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| 538DK           | 30     | 14.      |          |          |        |
|                 |        | 2±1.0^B^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| F~1~ 538DK x    | 14     | 19.      |          |          |        |
| Delisa          |        | 6±0.5^A^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| F~2~ 538DK x    | 150    |          | 113      | 37       | 0.01   |
| Delisa          |        |          |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| Delisa          | 30     | 19.      |          |          |        |
|                 |        | 6±0.7^A^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| 587DK           | 30     | 13.      |          |          |        |
|                 |        | 1±1.0^B^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| F~1~ 587DK x    | 12     | 21.      |          |          |        |
| Delisa          |        | 9±1.1^A^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| F~2~ 587DK x    | 103    |          | 71       | 32       | 2.03   |
| Delisa          |        |          |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| Delisa          | 30     | 19.      |          |          |        |
|                 |        | 6±0.7^a^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| 588DK           | 30     | 12.      |          |          |        |
|                 |        | 1±1.2^b^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| F~1~ 588DK x    | 9      | 21.      |          |          |        |
| Delisa          |        | 8±2.0^a^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| F~2~ 588DK x    | 68     |          | 48       | 20       | 0.18   |
| Delisa          |        |          |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| Diva            | 30     | 28.      |          |          |        |
|                 |        | 1±1.8^A^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| 225DV           | 30     | 6.       |          |          |        |
|                 |        | 4±0.9^C^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| Aramir          | 30     | 30.      |          |          |        |
|                 |        | 4±1.4^A^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| 014AR           | 30     | 15.      |          |          |        |
|                 |        | 5±1.5^B^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| F~1~ 225DV x    | 8      | 28.      |          |          |        |
| 014AR           |        | 9±1.7^A^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+

+-----------------+--------+----------+----------+----------+--------+
| Table 2         |        |          |          |          |        |
| (continued) .   |        |          |          |          |        |
| Analysis of     |        |          |          |          |        |
| F~1~ and F~2~   |        |          |          |          |        |
| generation of   |        |          |          |          |        |
| the crosses     |        |          |          |          |        |
| 'mutant x       |        |          |          |          |        |
| parent variety  |        |          |          |          |        |
| and 'mutant x   |        |          |          |          |        |
| mutant'.        |        |          |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| Genotype        | No. of | Seminal  | No. of   |          | χ^2    |
|                 | an     | root     | F~2~     |          | ^~3:1~ |
|                 | alyzed | length   | plants   |          |        |
|                 | plants | (cm)     | with the |          |        |
|                 |        |          | p        |          |        |
|                 |        | x ± SD  | henotype |          |        |
|                 |        |          | of       |          |        |
+-----------------+--------+----------+----------+----------+--------+
|                 |        |          | parent   | mutant   |        |
|                 |        |          | variety  |          |        |
+-----------------+--------+----------+----------+----------+--------+
| Diva            | 30     | 28.      |          |          |        |
|                 |        | 1±1.8^A^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| 225DV           | 30     | 6.       |          |          |        |
|                 |        | 4±0.9^C^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| Aramir          | 30     | 30.      |          |          |        |
|                 |        | 4±1.4^A^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| 035AR           | 30     | 17.      |          |          |        |
|                 |        | 6±1.2^B^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| F~1~ 225DV x    | 9      | 29.      |          |          |        |
| 035AR           |        | 4±2.7^A^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| Diva            | 30     | 28.      |          |          |        |
|                 |        | 1±1.8^A^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| 225DV           | 30     | 6.       |          |          |        |
|                 |        | 4±0.9^C^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| Aramir          | 30     | 30.      |          |          |        |
|                 |        | 4±1.4^A^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| 090AR           | 30     | 14.      |          |          |        |
|                 |        | 2±1.3^B^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| F~1~ 225DV x    | 10     | 28.      |          |          |        |
| 090AR           |        | 6±1.0^A^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| Aramir          | 30     | 30.      |          |          |        |
|                 |        | 4±1.4^A^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| 014AR           | 30     | 15.      |          |          |        |
|                 |        | 5±1.5^B^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| 035AR           | 30     | 17.      |          |          |        |
|                 |        | 6±1.2^B^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| F~1~ 014AR x    | 9      | 29.      |          |          |        |
| 035AR           |        | 8±1.3^A^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| Aramir          | 30     | 30.      |          |          |        |
|                 |        | 4±1.4^A^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| 035AR           | 30     | 17.      |          |          |        |
|                 |        | 6±1.2^B^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| 090AR           | 30     | 14.      |          |          |        |
|                 |        | 2±1.3^B^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| F~1~ 035AR x    | 10     | 28.      |          |          |        |
| 090AR           |        | 7±2.1^A^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| Aramir          | 30     | 30.      |          |          |        |
|                 |        | 4±1.4^A^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| 014AR           | 30     | 15.      |          |          |        |
|                 |        | 5±1.5^B^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| 090AR           | 30     | 14.      |          |          |        |
|                 |        | 2±1.3^B^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+
| F~1~ 014AR x    | 8      | 28.      |          |          |        |
| 090AR           |        | 5±1.0^A^ |          |          |        |
+-----------------+--------+----------+----------+----------+--------+

\* - the same letter in each individual cross indicates non significant
difference for P=0.05

Table 3. Analysis of seminal root length and root hair morphology in the
F~2~ generation of the cross 'mutant 225DV x Diva'

  ----------- ---------- --------- --------- -------------- -------------- ----------
  Number of                                  χ^2^~3:1A,a~   χ^2^~3:1B,b~   χ^2^~L~
  seedlings                                                                
  with a                                                                   
  phenotype                                                                

  A.B.        A.bb       aaB.      aabb                                    

  129         5          7         46        1.11           0.52           152.72\*
  ----------- ---------- --------- --------- -------------- -------------- ----------

\*χ^2^~L~\>3.84, P=0.05

A.B. -- parental phenotype (long seminal root, normal root hair), A.bb
-- recombinant phenotype (long seminal root, short root hairs), aaB. --
recombinant phenotype (short seminal root, long root hairs), aabb --
mutant phenotype (short seminal root, short root hairs).

**References**

Aeschbacher, R.A., Schiefelbein, J.W., Benfey, P.N. (1994). The genetic
and molecular basis of root development. Plant Physiol. Plant Mol. Biol.
**45**, 25-45.

Baskin, T.I., Betzner A.S., Hoggart, R., Cork, A., Williamson, R.E.
(1992). Root morphology mutants in *Arabidopsis thaliana*. Aust. J.
Plant Physiol. **19**, 427-438.

Baskin, T.I., Cork, A., Williamson, R.E., Gorst, R. *(*1995). *STUNTED
PLANT1*, a gene required for expansion in rapidly elongating but not in
dividing cells and mediating root growth responses to applied cytokinin.
Plant Physiol. **107**, 233-243.

Benfey, P.N., Linstead, P.J., Roberts, K., Schiefelbein, J.W., Hauser,
M-T., Aeschbacher, R.A. (1993). Root development in *Arabidopsis*: four
mutants with dramatically altered root morphogenesis. Development
**119**, 57-70.

Di Laurenzio, L., Wysocka-Diller, J., Malamy, J.E., Pysh, L.,
Helariutta, Y., Freshour, G., Hahn, M.G., Feldmann, K.A., Benfey, P.N.
(1996). The *SCARECROW* gene regulates an asymmetric cell division that
is essential for generating the radial organization of the *Arabidopsis*
root. Cell **86**, 423-433.

Hauser, M-T., Morikami, A., Benfey, P.N. (1995). Conditional root
expansion mutants of *Arabidopsis*. Development **121**, 1237-1252.

Inukai Y., Miwa, M., Nagato, Y., Kitano, H., Yamauchi, A. (2001) *BRL1*,
*BRL2* and *CRL2* loci regulating root elongation in rice. Breed. Sci.
**51**, 231-239.

Tsuchiya, T. (1974). Root characters of curly mutants in barley. BGN
**4**, 88-91.

Murashige, T., Skoog F. (1962). A revised medium for rapid growth and
bioassays with tobacco tissue cultures. Physiol. Plant. **15**, 437-497.

Tsyganov, V.E., Pavlova, Z,B., Kravchenko, L.V., Rozov, S.M., Borisov,
A.Y., Lutova, L.A., Tikchenovich, I.A. (2000). New gene *crt (curly
roots)* controlling pea *(Pisum sativum* L*.)* root development. Annals
of Botany **86**, 975-981.

Yao, S.G., Tageta, S. Ichii, M. (2002). A novel short-root gene affects
specifically early root development in rice (*Oryza sativa* L*.).* Plant
Science **163**, 207-215.

Yao, S.G., Tageta, S. Ichii, M. (2003). Isolation and characterization
of an abscisic acid-intensive mutation that affects specifically primary
root elongation in rice (*Oryza sativa* L.).Plant Science **164**,
971-978.