ALFOUSSEINY MAHAMANE MAIGA
DEVELOPMENT OF SORGHUM HYBRIDS WITH HIGH LYSINE AND THREONINE CONTENT IN SOUTHERN MALI
ABSTRACT
Sorghum [Sorghum bicolor (L.) Moench] is one of the main cereals grown in Mali. It constitutes essential food sources of energy, protein, vitamins, and minerals for rural populations in the country. However, sorghum is poor in minerals and protein especially lysine, threonine, important elements for children's nutrition and nutritional value of resource-poor farmers in Mali. It is therefore important to provide the population with high-yielding hybrids sorghum, more nutritious and adapted to the agro-ecological conditions of the country. The aim of this study was to contribute to the improvement of human nutrition by the development of fortified hybrids sorghum adapted to the agro-ecological conditions of Mali. To this end, the research was to develop inbredlines sorghum containing high lysine and threonine using the single seed descends method, develop female parent lines with high lysine and threonine content, evaluation of sorghum hybrid rich in lysine and threonine content in different sites, and determine the interrelationships between organic (lysine and threonine) inorganic (iron and zinc) content and plant agronomic traits. However, three Populations: 216-2BCTP1// P851171, 150B// P851171 and 12B// P851171 were developed with 80, 104, and 108 lines respectively. Two populations 12B// P851171 (2831kg-ha) and 216-2BCTP1// P851171 (2997 kg-ha) were more productive. A total of 103 lines were selected among the populations within the sites and 9 lines out of the 103 seem to have some good adaption traits in both sites Sotuba and Kolombada. Nine lines combine sterile cytoplasm reaction, good grain quality with high lysine and threonine content. As for the development of female parent lines with high lysine and threonine content, twenty-six lines were maintainer of sterility (B lines). Thirty-three lines were restorer of fertility (R lines). The nine B lines had a good grain qualities and endosperm textures. Regarding the evaluation of sorghum hybrid rich in lysine and threonine content in different sites interesting results were found, Male parents KO-BC1-F6-1053, SB-BC1-F6-1090, SB-BC1-F6-1036, SB-BC1-F6-1053 and female parent 216-2AP4-5 had a good general combining ability (GCA) for studied characters. The gain in grain yield of the best hybrids varied from 6.36 to 100 % compared to the better parent. Twenty hybrids had significant better parent heterosis for grain yield. In terms of earliness nine hybrids had a gain of negative better parent heterosis. For panicle length, grain number per panicle, lysine and threonine content a significant positive better parent was obtained. Ten hybrids got a better parent heterosis for primary branches per panicle. The number of whorls, most of the hybrids had a good better parent heterosis. The mineral content (Iron and zinc), four hybrids obtained a better parent heterosis for ion and then zinc, seven hybrids obtained a significant better parent heterosis. The hybrids (216-2AP4-5/SBBC1-F6-1105, 216-2AP4-5/SB-BC1-F6-1090, 216-2AP4-5/SB-BC1-F6-1036, 216-2AP4-5/KOBC1-F6-1053, 216-2AP4-5/BE-BC1-F6-2070, 12A/SB-BC1-F6-1036 and 12A/SB-BC1-F6-1090 more productive, stable and well adapted. As for, the inter relationships between organic (lysine and threonine) inorganic (ion and zinc) content and plant agronomic traits, the fortified hybrids 216-2AP4-5 / KO-BC1-F6-1053, 216-2AP4-5 / BE-BC1-F6-1105, 216-2AP4-5 / SB-BC1-F6-1090, 216-2AP4-5 / SB-BC1-F6-1105, 12A / SB-BC1-F6-1036, 216-2AP4-5 / SB-BC1-F6-1036, 12A / SB-BC1-F6-1105 and 216 -2AP4-5 / SB-BC1-F6-1053 had a grain yield over 4 tons and better components of yield and then which combined with a high amino acid and mineral content. Plant height, primary branch number per panicle, grain number per panicle, lysine, threonine content and grain yield had high genetic advance as percentage of mean. At phenotypic and genotypic level, significant correlation on grain yield through plant height, panicle length, primary branch per panicle, grain number per panicle and number of whorls per panicle were found. Based on the path analysis, positive and significant direct and indirect effect of correlation were observed in this work for cycle, grain quality, panicle length, primary branch per panicle, grain number per panicle and number of whorls per panicle at phenotypic level