Progress check of yielding ability and stability of selected pre-release bread-wheat cultivars in Zimbabwe

Abstract

The Crop Breeding Institute (CBI) develops new bread-wheat varieties as part of its research mandate. These are tested every year in multi-environmental trials (METs) so as to identify best performers suitable for commercial release. Here, we used METs’ datasets collected across 57 locations in Zimbabwe during the 2009–17 winter seasons, on yield and agronomic performance of CBI-bred, 156 advanced experimental lines and 69 check cultivars. Twenty-five genotypes were tested each year, but the number of sites varied accordingly. The wheat genotypes were planted using an alpha (0.1) lattice design replicated thrice, and each replication constituted five incomplete blocks, with a block size of five. Significant differences in grain yield (GY) on some locations, as well as, significant GE interactions on GY were observed. GY averages of the best five experimental lines in the year 2013 and 2015 significantly differed from those of the best five check cultivars. Furthermore, yield increments were shown from the season, 2010–15, and GY averages of the best five experimental cultivars, successively differed between these seasons. Significant correlations were shown between GY and the other agronomic traits, particularly days to anthesis and days to physiological maturity. Experimental genotypes identified as G12|2014 (7.3 tha−1), G8|2013 (5.5 tha−1), and G8|2009 (5.4 tha−1) showed superior yield performance and stability hence, can be recommended for commercialization. Generally, an observable trend in yield increments was observed between the seasons, 2009–17, and experimental lines that showed superior performance can be possible targets for gene introgressions and integrations in breeding programs in the other regions.