Effect of Heterogeneity and Heterozygosity on Agronomic Performance of the Semi-arid Grown Faba Bean (Vicia faba L.)

Abstract

In faba bean, the genotypically heterogeneous structure of its
population has an important impact on yield performance and remains the
major constraint a plant breeder has to contend with to improve the crop
yield. The aim of this study was to evaluate the effect of heterogeneity and
heterozygosity on yield performance of the semi-arid grown faba bean. Five
faba bean inbred lines (in S6 generation), F1 and F2 generations as well as
mixtures formed by blending an equal amount of seeds from each of them to
produce line mixture, F-1 mixture and F2-mixtures were used to execute the
experiment. The seeds of the pure lines, lines mixture and F1-and F2-mixture
were grown in two consecutive seasons (2014/2015-2015/2016) at the
Experimental Farm, Faculty of Agriculture, Shambat in a randomized
complete block design with three replicates. Data were collected on yield and
yield components. Heterogeneity in lines mixture caused a positive and
significant increase of +16% in number of pods per plant and 11% increase in
both 100-seed weight and yield compared to pure lines performance, whereas
heterogeneity in "pure lines+ F1-hybrid and that in pure lines mixture+ F1-
hybrid mixture gave significant positive yield of 28% and 24% , respectively
when compared to the performance of F2 and F2 mixture. Heterozygosity in

F1 gave significant positive yield increase of 67% when compared to lines
performance, whereas heterozyosity in F1-mixture gave significant yield
increase of 60% when compared to lines mixture. The same effect was shown
by yield components. The results clearly indicate the great positive effect of
heterozyosity compared to that of heterogeneity, which indicate the
possibility of production of synthetic cultivars as alternative to the still not
yet commercially produced hybrids in faba bean.