خصوصیات مورفوفیزیولوژیک مرتبط با عملکرد ژنوتیپ های سورگومدانه ای در شرایط تنش رطوبتی

Abstract

Abstract This study was conducted in order to evaluation effect of drought stress on some morph-physiological traits correlated with yield in ten-grain sorghum genotypes kept at National Plant Gene Bank of Iran. Field experiments were in 3 different conditions including normal condition and two water deficit conditions in vegetative and reproductive stage in Torogh Agricultural Research Station (Khorasan Razavi Agricultural and Natural Resource Research Center, Mashhad-Iran) using complete randomized block design with 3 replications. In non stress experiment, irrigation operated normally and for 2 another experiments (1) drought stress treated in vegetative period (from 4 leaves up to flowering stage) and (2) drought stress treated in reproductive period (from flowering up to maturity), irrigation was stopped during of stress period. Traits were analyzed included: time of flowering, plant height, and number of fertile tillers, stem diameter, length of panicle, shoot dry matter, seed yield per plant, and 100 seed weight. The results of this study showed genotypes had significant difference (p<0.01) in all traits except seed yield per plant and100 seed weight in three conditions. Highest yield per plant was obtained on normal condition and this trait were decreased 11 and 42.4 percent in reproductive and vegetative period drought stress experiments compared to normal condition. Days to flowering and plant height had significant and positive correlation with biological yield per plant at all conditions. Results of multiple linear regression analysis revealed that days to flowering as a independent variable described and determined changes of biological yield per plant in normal condition as dependent variable truly (P<0.01, R2Adj=0.85) and drought stress in reproductive and vegetative period(p<0.01, R2Adj =0.79 and R2Adj =0.53) respectively. Cluster analysis with ward method at three conditions showed different groups of genotypes in each dendrogram, that indicated significant genetic variation for these investigated traits among sorghum genotypes under well watered and drought condition and it might be possible to used these characters in sorghum breeding programs. Keywords: Water deficit, Growth phonological stages, Cluster analysis