Genetic Studies for some Bean Traits in Relation to Stability and Insect Infestations

Abstract

This research was carried out at a private farm located at Qaha, Qalyubia Governorate, Egypt during the two successive summer seasons of 2018 and 2019 to estimate the stability parameters of ten dry bean (Phaseolus vulgaris L.) genotypes for yield, insect infestation and some economic traits under different planting densities as well as to assess the annual variation of some insect pests through different growing densities and seasons in relation to certain climatic factors, synchronization of plant age with insect infestation percentage on plant due to insect activity. There were significant genotype × densities interactions for the studied bean’s traits, i.e., number of days to flowering, pod length, 100-seeds weight, number of pods/plant, yield/feddan and insect infestation. Combined analysis of variance revealed significant differences among genotypes for all studied traits. Pooled deviation mean squares for number of days to flowering, yield/fed. and insect infestation were not significant suggesting the consistency of the genotypes yielding ability under environmental conditions tested. The high yielding genotypes G6, G1 and G10 produced high yielding performance based on wide adaptation and stability of performance over all environments. Genotypes G3, G5, G7 and G10 were insensitive to environmental changes and could be recommended for cultivation under all conditions. Genotype G8 also had minimum aphid infestation over range of environments showed below regression coefficients for yield/fed. and insect infestation and low deviation from regression, indicated specific adaptability of this genotype to unfavorable environments. Genetic variation (σ2g) was large in magnitude compared to error one (σ2e) in all studied traits of all cases except pod length in all densities of 2nd season (Env. 5-8) and number of pods under 10 cm/2 rows of Env.8, reflecting the genetic differences among genotypes for all studied traits except of those two cases. The population of both leaf miners (Melanogromyza phaseoli) and aphid (Aphis craccivora Koch) was observed from the third week of March (5th week after planting date) and continued till to 3rd week of May (14th week after planting) and reached to a peak level 55.2 and 85.9% for aphid and leaf miners during 9th and 11th weeks after planting date, respectively, i.e. 2nd and 4th week of April. Genotype G8 interacted with planting space of (5 cm ×2 rows) were explained the lowest Melanagromyza phaseoli (Tryon) and Aphis craccivora Koch, infestations (18.8% and 12.6%, respectively) followed by G1 and G5 with the same planting space for leaf miners (29.6%) and aphid (15.3%) infestations, respectively.