Genetic study of wheat (Triticum aestivum L.) root characteristics under drought stress condition

General and specific combining ability and gene action for some traits as root dry weight and root: shoot ratio under drought stress condition in bread wheat genotypes were studied, using eight parents (six lines and two cultivars) in a diallel crossing design in 2002. The 28 F1 hybrids and the eight parental genotypes were sown in a randomized complete block design with four replications in a research greenhouse. Results of the analysis of variance showed that differences between genotypes were significant for root dry matter and root: shoot dry matter in both normal and drought stress conditions. It was also observed that the majority of the genetic variance for root dry matter was due to additive gene action. Under normal conditions, the parents 7007-2 and Shahpasand had the highest general combining ability (GCA) for root dry matter trait and considered to be the best general combiner for root to shoot dry matter ratio under in both conditions. Results also indicates that, the over-dominant gene actions under stress condition were the most contributors to the inheritance of both traits. The lines 5593/2 and 524-4 had the maximum dominant genes and the minimum recessive genes, for both traits under drought stress respectively. Key words: Wheat root, Combining, gene effect, Tolerance, Drought stress.Scientific Short ArticleThe effect of row and planting spacing on yeild in the white bean cv. DanshkadehKahraryan7, B. and R. Fatemy8ABSTRACTIn order to study the effects of row and plant spacing on the grain yield of withe bean, cv. Daneshkadeh, a field experiment was camied-out in Khomein field Research station in 2002 cropping season. Four levels of row spacing, 30, 40, 50 and 60 cm and three levels of plant spacing on row, 5, 10 and 15 cm were studied in split plot arrangement using randomized complete block design with four replications. Four levels of row spacing were assigned to main plots and three levels of plant spacing to sub plots. The results showed that increasing row spacing and plant spacing, i. e. decreasing plant density, the grain yield significantly decreased. The highest grain yield (2605 kg/ha) was obtained from the combination of 30 * 5 cm, row and plant spacing, respectively.