Yield of the Testcrosses Across the Different Environments

Abstract

Purpose: The main purpose of this paper was to determine the yield of the testcrosses across the different environments. Methods: The lines used in the study were derived from a segregating population in the F4. They were crossed to two single cross testers CIMMYT Tester A (CML312/CML442) and Tester B (CML395/CML444) through the Line by tester mating design. The 98 crosses developed through line by tester cross of 49 lines in the F4 and two testers Tester A and Tester B were studied for resistance to NLB and other yield related traits including : days to anthesis, days to silking, ear aspect, plant height, ear height, field weight and Grain moisture. The experiment was conducted in the 2017 main growing season in three mid-altitude maize growing regions of Kenya (Kakamega, Muranga, Embu).The yield was evaluated by analyzing the grain weight of the crosses using CIMMYT IMIS field book. The data collected for NLB and other yield related traits was analyzed using the CIMMYT META R and AGD R (2015). In the analysis, lines, plots and site were used as fixed factors. Replications, incomplete blocks were used as random factors Results: The study found out that the maize crosses exhibited different yield performance across the three locations even under similar agronomic management practices. Testcrosses developed with Tester A recorded higher yields in Kakamega and Embu while in Muranga the crosses developed from Tester B recorded higher average yields. Unique Contribution to Theory, Practice and Policy: The study recommeded that The top performing crosses could hence be subjected to further trials hence recommended for high yielding varieties in best suited regions in the country. The lines could further be developed to breed for high performing hybrids that would be best suited for different agro-ecological zones across the country in different combinations.