PRODUCTIVITY AND CHOCOLATE SPOT AND RUST DISEASES OF SOME FABA BEAN CULTIVARS UNDER DIFFERENT SOWING DATES AND SALICYLIC ACID CONCENTRATES

Abstract

Two experiments were conducted at the experimental Farm at Tag El-Ezz, Dakahlia, Egypt, during 2008/2009 and 2009/2010 to evaluate the productivity, chocolate spot and rust diseases for five faba bean cultivars under two sowing dates and three salicylic acid concentrations. Sowing date November 15th gave the highest values of morphological and yield characters while, gave the lowest values of chocolate spot and rust compared with October 15th sowing date in both seasons. Seed yield/fed. recorded 8.17 and 7.49 ardab**/fed*. for sowing date November 15th and 6.17 and 6.15 ardab/fed. for the sowing date October 15th in both seasons, respectively. Giza 716 produced the highest seed yield/fed. in the second season, but no significant differences were observed between faba bean cultivars in the first season. The maximum reduction in severity of chocolate spot and rust diseases accrued under the application of salicylic acid (SA) at 150 mg/L. at the two sowing dates in both seasons. Whereas, led to marked improvement in morphological characteristics and yield. The interaction between sowing date and faba bean cultivars led to significant increase in plant height, straw yield, seed weight/plant and seed yield in both seasons. The maximum reduction of chocolate spot and rust disease severity was recorded with Giza 716 in November 15th planted under application of SA at 150 mg/L. The correlation coefficient cleared significant positive correlation between seed yield and each of individual studied characters. Multiple regression analysis indicated that the relative contribution for all characters gave 93.06% from the total variations of yield. Stepwise regression revealed that three out of six variables significantly affected seed yield/plant, these variables were seed weight, number of branches and number of pods per plant. The present investigation recommends to planting Giza 716 cultivar in November 15th with spraying of SA (150mg/l.) after 50 and 70 days from sowing to decrease the severity of chocolate spot and rust diseases and improve faba bean productivity.