The study of genetic diversity and relationships of major agronomical traits for several wheat accessions of National Plant Gene Bank of Iran

In this study 512 wheat accessions and three cultivars، named Kavir، Roshan، Mahooti (as check varieties) were evaluated in a field experiment of National Plant Gene Bank of Iran (NPGBI) during 2009-2010، using augmented design in 16 block، in which each block contained 35 samples. Agronomical، morphological and phenological characters such as germination percentage، days to heading، days to flowering، days to maturity، days from heading to maturity، days from flowering to maturity (duration of grain filling)، plant height، spike length، stem thickness، number of nodes، spike density، awn of spike، glume color، glume hairiness، number of spikelets/spike، number of flowers/spikelet، number of seeds/spike، hundred seeds weight، seed weight of 5 spikes and seed weight/ plot were evaluated according to IPGRI descriptors. Results of descriptive statistics for quantitative traits revealed the most value of coefficient of variation (CV) on seed weight / plot (30%) and seed weight of 5 spikes (23%)، respectively. Minimum value of CV was detected for phenological traits such as days to maturity (2%)، days to heading (3%) and days to flowering (3%)، respectively. Results of Shannon index for qualitative traits revealed the most variation on awnletted of spike (H0. 92='') and minimum variation was observed on glume hairiness (H0. 37=''). The strongest correlation with seed weight/ plot were observed with plant height (r = 0. 23**) and hundred seed weight (r = 0. 23**)، respectively. Number of seeds/spike and hundred seed weight، explained 95. 2 percentage variation of seed weight on 5 spikes in stepwise regression analysis. Path analysis revealed that direct effects of seed number /spike and hundred seed weight on seed weight on 5 spikes were 0. 77 and 0. 66، respectively. Factor analysis according to principal components analysis and varimax rotation revealed that overall 74. 1% of total variation could be explained by 5 factors. Cluster analysis by Ward method grouped the germplasms from 21 countries in three clusters.