Morphological diversity and agronomic evaluation of promiscuous varieties of soya bean

Abstract

Promiscuous varieties have the potential to increase soy abean (Glycine max (L.) Merrill) production of resource poor farmers who cannot afford artiticial inoculum. Some varieties grown by smallholders are known to be promiscuous but their yields are reported to have declined overtime, yet researchers questions their purity. It is suspected that these varieties are made up of mixtures of genotypes with varying  nodulation capacities. A study was carried out to quantify diversity in two  promiscuous  varieties, Local, and A& II using morphological markers to initiate mass selection to reconstitute the original varieties. Eight  Phenotipic Groups (PGs) were identified in the variety Local mainly based on days to flowering, growth habit and flower colour, whereas in the variety A& 11, days to flowering, number of  primary branches, and response to rust infection revealed seven PGs. A second  study evaluated the agronomic performance of the PGs in comparison with a specifically nodulating commercial variety Storm. Five of the PGs identified in A 711 had significantly (P<O.Ol) higher grain yield than the commercial standard. All eight PGs identified in Local yielded the same as the commercial standard.

Key Words : Genotype, Glycine max, nitrogen fixation, nodulation