فصلنامه علوم زراعی ایران
سال ششم شماره 4 (پیاپی 24، زمستان 1383)

Forage yield and some physiological traits of a forage sorghum cultivar (Speed feed) was studied in three irrigation intervals 4, 7 and 10 days in the Azad university of Iranshahr in 2003 cropping season. The experimental deasign was split plot based on randomized complete blocks with three replications. Irrigation intervals were studied in main plots and plant density of 8, 12 and 15cm were assigned to sub-plots. Planting was carried out in May 5, 2003. Different physiological traits associated to forage yield and its components were measured durring growing season. Analysis of variance and mean comparison were porformed using the principles of split plot design and DMRT, respectively. The best irrigation intervals and plant density determined. In this expriment the best irrigation interval, were 4 and 7 days and the best plant density was 12cm. Results indicated that fresh forages are in the same group as irrigation interval, of 4 and 7 days, and the best plant density was 12cm. However, after drying the dry forage at first irrigation level and the second plant density level (37130 kg/ha) was the highest.

In order to evaluate the interaction effects of plant spacing and nitrogen on growth and grain yield of rice, an experiment was conducted in Kushkak agricultural research center in 1998 cropping season. The experimental design was split-split plot in which nitrogen was assigned to main plots, plant spacing to sub-plots and weed density to sub-sub plots. With increase in rice plant spacing from 2020 to 2525 cm, rice grain yield increased. Among yield components, the number of panicle per plant (11.7vs 13.7) and number of grain per plant (782.2 vs 1202.7) significantly increased. The increase in Barnyardgrass weed density significantly reduced rice grain yield (from 4328 to 2587 kg ha-1). Rice grain yield increased by increasing nitrogen rate (from 2818 to 3802 kg ha-1) but there was no significant difference between 80 and 120 kg/ha-1. Nitrogen fertilizer efficiency decreased when the rate of nitrogen increased. Harvest index reduced by increasing the rate of nitrogen, but this reduction was not significant.

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.

In 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.