IMPROVING SEED YIELD AND PROTEIN CONTENT OF COMMON BEANS (PHASEOLUS VULGARIS L.) THROUGH MUTATION BREEDING

Abstract

The common bean is a staple food and source of protein in many African countries. To date, genetic improvement of common bean in Egypt lags behind compared with other legume crops which mainly due to limited genetic resources. This study was carried out in three consecutive growing seasons (2016, 2017 and 2018) at Sakha Experimental Station, Horticulture Research Institute (HRI) at Kafr El-Sheikh governorate, Egypt. The study aimed to increase genetic variations in Nebraska bean cultivar through mutation breeding for selection of novel bean lines with higher seed yield and protein content. The experiment was arranged in a randomized complete blocks design (RCBD) with three replications. Seeds of Nebraska bean cultivar which widely grown in Egypt were treated with gamma rays three different doses (10, 20, and 30 kr), and selection was made at M2 and M3 generations for desired traits related to vegetative growth parameters, pod characteristics and seed yield components. These traits were significantly affected by irradiation treatments in M1 generation, and changes in plant height, number of branches per plant, number of pods and seeds per plant were generally favorable in M2 generation than control (un-irradiated plants). Analysis of variance in M3 generation showed a highly significant difference among M3 lines and control for vegetative and agronomical traits except for the traits of number of days to first flower and number of seeds per pod. Among 25 M3 lines, ten mutant lines were produced higher seed yield (4.3 to 108.6%) and protein content (0.08 to 2.79%) along with heavier seeds (3.5 to 35%) than original parent Nebraska cultivar. Hence, these lines should be evaluated for the desired traits and wide adaptability to biotic and abiotic stress to release new improved varieties in Egypt.