ADVANCES ON HETEROSIS AND HYBRID BREEDING IN FABA BEAN (VICIA FABA L.)

Abstract

SUMMARY Faba bean, formerly broad bean, is gaining importance as a grain legume for protein security of demographically expanding and climatically changing world. Yield instability, however, remains major constraint in the cultivation of this important crop and it is contributing to significant decrease in acreage under this crop worldwide. Exploitation of heterosis has now long been established as a strategy not only to increase the yield but also to stabilize it in open pollinated crops. The cytoplasmic male sterility has already been discovered and positive and significant heterosis for seed yield component characters has been repeatedly demonstrated in the partially allogamous faba bean. Despite these developments, all the attempts for full exploitation of heterosis in the form of commercial production of F 1 hybrid have failed due to phenotypic instability of the cytoplasmic male sterility. The goal of development of hybrid varieties in this species remains unrealized yet, although partial exploitation of the heterosis in the form of synthetic varieties has been reported. The present review of research attempts to synthesize the literature on heterosis research in faba bean along with the description of current and future breeding objectives in context of the unique floral and pollination biology, CMS instability and constraints in hybrid breeding.