# Genetic and Environmental Factors Associated to Glutenin Polymer Characteristics of Wheat
## 3 Results and Discussion
### The Polymer Characteristics Responded More to Environmental Factors than Genetic Factors  
ANOVA, when computed with genotypes, locations, or years, revealed the maximum variance explained by each of these factors used as unique explanatory variate. As expected, genetic differences were prominent in GH variations, but the percentage for TW, although significant, was low. Of particular interest for the polymer characteristics, the part of phenotypic variance explained by genotypes are relatively high: 55.0%, 79.6%, and 61.5% for Mw, Rw, and PI, respectively. The phenotypic variance of each polymer characteristic was better explained by environmental factors; greater \(R^{2}\) percentages were found for the locations or for the years of experimental trial (Table 1). This higher influence of environmental factors, as compared to the genetic factor, initially noticed for polymeric proteins [20] is also confirmed here by the broad-sense heritability calculus. The average H\({}^{2}\) coefficients computed for the polymer characteristic were similar or lower than the H\({}^{2}\) of PC, well-known to be largely influenced by environment. Although the years and locations were of higher effectiveness than cultivars on the phenotypic variations, the multiple comparisons performed between the 192 cultivars showed that at least three distinct groups of cultivars (of low, medium, or high value) could be obtained for each polymer characteristic (data not shown). Being of low heritability, the polymer characteristics can be employed, however, for phenotypic evaluation and cultivar ranking in the breeding program. The analysis of the alleles at the six glutenin loci, encoding HMW-GS and LMW-GS, offered the opportunity to better approach their genetic influence on the phenotypic variation of polymer characteristics.  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline
**Parameters** & **Total** & **Mean 1** & **S.D. 2** & **Min 3** & **Max 4** & **R2 \%** & **R2 \%** & **R2 \%** & **R2 \%** & **R2 \%** & **H2 (4)** \\  & **Samples** & & & & & **(192)** & **(11)** & **Year (4)** & **H2 (4)** \\ \hline PC (\%dm) & 883 & 11.4 & 1.02 & 8.7 & 15.1 & 25.6 & 42.1 & 0 & 24.6 \\ GH & 883 & 51.9 & 23.66 & \(-\)6.3 & 112.8 & 83.8 & 9.1 & 4.8 & 78.7 \\ TKW (g) & 883 & 45.9 & 4.52 & 29.0 & 64.9 & 45.9 & 26.4 & 7.3 & 52.3 \\ TW (kg/hL) & 883 & 78.5 & 3.57 & 64.0 & 86.3 & 4.3 & 59.6 & 56.3 & 35.0 \\ Mw (kDa) & 885 & 9554.4 & 5485.6 & 1142.0 & 48.777.5 & 55.0 & 70.1 & 59.1 & 11.8 \\ Rw (nm) & 885 & 42.4 & 20.94 & 6.7 & 116.2 & 79.6 & 85.2 & 82.6 & 25.0 \\ PI (Mw/Mn) & 885 & 12.58 & 11.81 & 1.04 & 82.94 & 61.5 & 85.6 & 74.1 & 21.2 \\ \hline \hline \end{tabular} (1) Mean value, (2) Standard Deviation, (3) Minimum value, (4) Maximum value.  
\end{table}
Table 1: Values of statistical distribution of the 192 cultivars experimented in 11 locations for protein content (PC); grain hardness (GH); thousand kernel weight (TKW); test weight (TW); and the polymer characteristics: molecular mass (Mw), gyration radius (Rw), and polydispersity index (PI). The percentage (\(R^{2}\)%) of phenotypic variance was obtained using one factor ANOVA, and the heritability H\({}^{2}\) coefficient was averaged over the H\({}^{2}\) computed per experimental year.