Effect of Sowing Date of Resistant and Susceptible Faba Bean, <i>Vicia faba</i> L. Cultivars on <i>Orobanche crenata</i> Forsk Seed Bank and Faba Bean Production

Abstract

The broomrape<i>, Orobanche crenat</i>a Forsk (Orobanchaceae) is a serious annual parasitic weed that causes considerable losses in many major crops including faba bean (Vicia faba L.). In Egypt: losses due to <i>O. crenata</i> parasitism may reach 40 to 100%. Despite using several methods to control <i>O. crenata,</i> success has not been achieved. The impact of different control tactics on <i>O. crenata </i>is not well understood<i>.</i> However, Sowing date appears to be one of the potential solutions for controlling <i>O. crenata</i>. In this work we investigated the effect of sowing dates on both the level of infection by <i>O. crenata</i> and the pod yield of faba bean using resistant (Giza 843) and susceptible (Nubaria 1) faba bean cultivars in naturally <i>Orobanche</i> infested soil. Moreover, the <i>Orobanche</i> seeds production was determined as an indication of seed bank future adding in soil. Under <i>Orobanche</i> free conditions, Nubaria 1 cultivar produces more pod yield than the resistant cultivar. The results demonstrated that, late sowing (3 weeks after normal sowing date) reduced significantly the number of emerged <i>O. crenata</i> shoots for both the resistant and the susceptible cultivars., Late sowing similarly contributed to a significant increase in pod yield (dry weight (kg)/plot) especially for Giza 843 (5.15 ± 0.02 Kg /plot), the resistant cultivar, which produced much higher pod yield than the susceptible Nubaria 1 cultivar (2.98± 0.06 Kg /plot) during the first season (2019 - 2020). During the second season (2020 - 2021), the pod yield was (3.85 ± 0.10) and (5.49± 0.76) Kg/plot for Giza 843 and Nubaria 1 cultivars, respectively, compared with the early sowing date. Furthermore, regarding both seasons, the seeds number per spike decreased significantly with the late sowing date in both the resistant and susceptible cultivars.