DOI: 10.5061/dryad.ttdz08m44
title: Data from: Combining ability of experimental maize lines for yield and aflatoxin in the southeastern USA

description: Aflatoxin contamination of maize (Zea mays L.) grain presents risks to
 animal and human health and causes economic losses for growers,
 particularly in the southeastern United States. Development of hybrids
 with genetic resistance to aflatoxin contamination by Aspergillus
 flavus will reduce these risks. Two factorial crossing experiments were
 conducted to evaluate yield, agronomic traits, and aflatoxin in maize
 hybrids. In Exp. 1, 18 aflatoxin-resistant (GT) lines were each crossed to
 six testers. In Exp. 2, 13 of the same lines were each crossed to 10
 different testers. Each experiment was conducted for two years at Tifton,
 GA and commercial check hybrids were included for comparison. 
 Ears were inoculated with A. flavus isolate NRRL 3357 using the
 side-needle technique 14 d after silking. Aflatoxin was quantified after
 harvest. Broad sense heritability for aflatoxin was low in Exp. 1 (H2 =
 0.09) but was higher in Exp. 2 (H2 = 0.27). Heritability was moderate to
 high for plant height (H2 = 0.49–0.51) and days to silking (H2 =
 0.54–0.72).  Among experimental lines, GT1209 and GT1309 had
 consistent positive general combining ability (GCA) for yield, whereas
 GT1203 and GT1204 had consistent negative (favorable) GCA for aflatoxin.
 Significant GCA effects, both positive and negative, for aflatoxin were
 also observed among testers in both experiments. Some experimental hybrids
 had yields that were comparable to commercial checks while also having
 lower aflatoxin, demonstrating the progress made in improvement of both
 traits in maize hybrids adapted to the Southern United States.
description: # Data from Combining Ability of Experimental Maize Lines for Yield and
 Aflatoxin in the Southeastern USA --- This dataset contains all raw data
 from all four years of the study in Excel (.xlsx) format. Missing data are
 represented by a dash (-). Male and female parents of commercial hybrids
 are unknown and are thus coded as missing data. ## Description of the data
 and file structure Data from each individual experiment are presented in
 individual tabs. In 2014 and 2015, two separate experiments for yield
 (tabs 2014yld and 2015yld, respectively) and aflatoxin (tabs 2014afla and
 2015afla, respectively) were conducted. Other agronomic traits, such as
 plant height, ear height, etc. were assessed in the 2014 and 2015 yield
 trials and are available in the 2014yld and 2015yld tabs. In 2018 and
 2019, yield and aflatoxin were assessed within the same experiment along
 with other agronomic traits. These data are available in tabs 2018all and
 2019all. Data are reported under the following column headings: * Plot_ID
 Unique plot number assigned within a year. * Rep Replication number. Each
 experiment contained four replications. * Range and Row. The unique
 position of each plot within the field can be defined by these two
 coordinates. * Entry# - Unique number assigned to each pedigree within a
 year. * Pedigree Pedigree for each specific entry or commercial name for
 checks. * P_female Female parent * P_male Male parent * Stand Number of
 plants in the two-row plot. 72 seeds were planted in each plot. * Ear_ht
 Height (cm) from ground to node of the primary ear * Plant_ht Height (cm)
 from ground to tip of the tassel * EP_Ratio Ratio of ear height to plant
 height * Anthesis Days from planting until 50% of anthers are shedding
 pollen * Silk Days from planting until 50% of silks are exposed * ASI
 Anthesis-silking interval days between anthesis and silking * %*Moisture
 Grain moisture at harvest as measured by the combine * Plot_Wt_lbs Raw
 plot weight (lbs) of grain as measured by the combine * TWT* lbs/bu Grain
 test weight (lbs/bu) as measured by the combine * kg_ha_15 Grain yield in
 kg/ha adjusted to 15% moisture * Lodging Total number of lodged plants. In
 2018 and 2019, stalk lodging and root lodging were counted separately. *
 %_lodging Total percentage of lodged plants * 5_ears_g In 2018 and 2019,
 the shelled weight (g) of the five ears sampled for aflatoxin analysis *
 5_ears_lbs - In 2018 and 2019, the shelled weight (lbs) of the five ears
 sampled for aflatoxin analysis * Plot_total_lbs In 2018 and 2019, the
 total weight of grain harvested from the plot (combine wt. + shelled ears)
 * Afla_ppb Grain aflatoxin concentration (ppb, or ng/g) determined by the
 Vicam Aflatest procedure * Log_afla+1 Aflatoxin concentration
 log-transformed as y = log(x + 1)