Breeding Dual-purpose Sorghum (Sorghum bicolor L. Moench) Varieties For Fodder and Grain Production

Abstract

A study was conducted at Shambat, in the Experimental Farms of the Agricultural Research Corporation and College of Agricultural Studies / Sudan University of Science and Technology, during 2010-2013 with the objectives of investigating the possibility of developing high yielding dual purpose fodder / grain sorghum varieties. 21 sorghum genotypes selected from a replicated breeding nursery comprising 122 genotypes were tested against 3 checks in Alpha lattice design with 3 replicates. Six dual purpose genotypes were identified and evaluated against a dual check under two harvest options across summer and winter seasons for two consecutive years. Split plot design was used with harvest option assigned to main plot. Data for forage and grain yields and their related traits were collected. Proximate analysis was carried out for some quality traits of grain and forage materials. Association study between different agronomic traits was carried out. The study revealed the possibility of selecting sorghum cultivars with high capacity for dual fodder/ grain production. This has been enhanced by the high significant differences encountered among genotypes for all studied traits. Six genotypes were identified as having the best performance for dual grain/fodder outyielding the standard dual check ‘Abnaffain ’. Of these, Abjaro seemed to be the best genotype combining the highest fodder and grain yields and was among the best in leaf to stem ratio. The Abu Sabein selections S.25Abu70 and S.03Abu70, though less leafy, ranked second to Abjaro in fodder/grain productivity and excelled Abjaro in earliness. ArfaaGadamak and WadAhmed, the standard grain checks, exhibited below average performance in both grain and fodder yields but were among the best in leaf to stem ratio. Abnaffain the standard dual check gave the lowest dry matter yield with below average grain yield. The best regrowth values were shown by the Sudangrass genotypes SG32_2A and SG08. The study revealed positive highly significant correlation between green matter yield and grain yield pointing to the possibility of simultaneously combining high levels of grain and fodder yields in one cultivar. This was further supported by the positive and highly significant correlation between plant height and each of grain and fodder yields. Correlations of days to flower with each of forage and grain yield were weak and insignificant allowing development of early and high yielding dual fodder/ grain cultivars. Differences among harvest options and genotypes were significant for grain yield, plant height and days to boot in both seasons. Genotype x harvest option interaction was highly significant for the three traits in both seasons indicating the need for evaluating the dual sorghum cultivars under different harvest options. To maximize grain and fodder yields from dual sorghum cultivars, different genotypes were suggested for different harvest options in different seasons. The study revealed that when harvesting forage from the main crop and grain from ratoon, the best choice is to grow S.25Abu70 during summer and the cultivar Abjaro during winter. Ratoon cropping had resulted in significant reductions in grain yield amounting to more than two thirds of that of the main crop. The study revealed that when harvesting grain and stover from the main crop, Abjaro ranked top in both attributes followed by Abu Sabein selections, but still farmers may favour growing Abu Sabein due to lateness of Abjaro unless the stover value of the summer season is high enough to justify growing Abjaro. The data presented for protein content of the grain revealed that ratooning has no negative impact on protein content. Abjaro was the best in forage quality in terms of protein content, NDF and ADF but it showed below average protein content of the grain. The study concluded that direct selection for high yielding dual fodder/grain sorghum cultivars is possible. High levels of grain and fodder yields coupled with some desirable agronomic traits could be incorporated in one sorghum cultivar. Dual sorghum cultivars should be assessed under different harvest options to maximize the benefits gained from developing dual fodder/grain cultivars. The traditional cultivar Abjaro and Abu sabein selections S.25Abu70 and S.03Abu70 were identified as dual fodder/grain cultivars under different harvest options. Future studies in collaboration with animal nutrition specialists should focus on developing dual sorghum cultivars having high stover quality with special emphasis on improved digestibility. Studies to maximize the benefits gained from dual cultivars should explore variety choice and cultural practices for different harvest options.