Understanding of Morpho-Physiological Variability on Iranian-Durum Wheat Landraces under Cold-Rainfed Conditions

The evaluation of gene bank germplasm collection for morpho-physiological traits is important in the breeding programs. Although phenotypic variation was considered, it is likely that this phenotypic variation is largely genetic and therefore directly useable for breeders, especially for those traits with high heritability such as heading and maturity time, plant height, kernel number and weight. In this study, to evaluate agronomic traits effective on yield, 252 Iranian durum landraces were studied for 3 years under cold dryland conditions at Maragheh Research Station (North West of Iran). Study carried out using augmented design at the first and second years. The results showed that some landraces had significantly higher grain yield than local checks in all three years. Based on correlation coefficient analysis, yield had a significant and positive correlation with plant height and 1000-seed weight. Moreover, days to heading and maturity had significant negative correlations with yield. In stepwise regression, days to maturity, plant height, and grain weight were significant and entered to model. In path analysis, days to maturity, plant height, and grain weight had the most direct effects on yield and their indirect effects were not noticeable in the first year. In the second year, direct effect of days to maturity was -0.27 and its indirect effect by decreasing 1000-seed weight were -0.14. In the third year, plant height had 0.70 direct effect on yield, but it was decreased to 0.59, because of indirect and negative effect of days to maturity (-0.11). Cluster analysis showed that landraces with few tillers, tall, early maturity and larger seeds, had higher yield. It could be concluded that early maturity, tallness, and seed weight are effective traits on increasing grain yield under drought conditions. Also, the existence of better landraces than local checks supports efforts of conservation and utilization of landraces in durum breeding programmes.