Performance of Maize Inbred Lines and Their Hybrids Under Varying Drought Stress Conditions in Mali

Abstract

Recurrent drought is one of the major constraints to maize production in West Africa. It can be devastating if it occurs for a long period, especially during flowering. Hybrid maize varieties that are tolerant to drought are not available. Therefore, many farmers in Mali have not yet adopted hybrid maize varieties. In this study, maize inbreds and hybrids were evaluated for their tolerance to drought and the gene effects conditioning performance under both drought and no drought conditions were studied to identify hybrids tolerant to drought stress that could be released. The association of inbred root characteristics and tolerance to drought was also evaluated. Hybrids generated from crosses between thirteen inbred lines were evaluated for drought tolerance. Seventy-eight hybrids and two checks were evaluated under water stress and non-water stress conditions across four environments during the off-season of 2010. The seventy-eight hybrids were obtained from a diallel cross of thirteen parents. The test sites included: Farako (10°50’00’’ North 6°51’0’’ West), Sotuba (12°39’47’’North 7°54’50’’ West) and Yanfolila (11°11’0’’ North 8°9’0’’). Two planting dates were used to create two different environments at Farako. The experiment consisted of a split-plot with water regime as the main plot and hybrids as the sub plots. The water regime consisted of a well watered plot where irrigation was supplied through-out the plant cycle and a drought imposed plot where irrigation was stopped 40 days after planting for 20 days. The sub-plots consisted of the 78 hybrids and checks arranged in an alpha lattice with two replications. Water stress increased anthesissilking interval resulting in reduced grain yield. Hybrid V841-73/9071 had the lowest grain yield reduction (35.3%) due to water stress, followed by CML 505/1368 (41.9%). Line 9071 has good root weight and good root number under stress while line1368exhibited good root number, good root length and good root weight under stress. The following Genotypes9071/CML442; CML442/TZ COMP3-C2-S2, 87036/CML442, CML505/1368, V481-73/CML442, C11O5/9071, J-16-1/TZ COMP3-C2-S2 and CML444/87036 performed well under both well watered and water stress conditions. The inbreds 9071 and CML442 exhibited the highest frequency of appearance as parents among the best hybrids both under well watered and water stress conditions demonstrating their superior SCA with some of the other parental inbreds studied here.