ASSESSMENT OF THE AGRONOMIC PRODUCTIVITY AND PROTEIN CONTENT IN 16 SOYBEAN GENOTYPES

Soybean is an important crop worldwide. It can be used for food, seed, fuel, vegetable oil, soy milk and is capable of biological nitrogen fixation. In Malawi, yields are generally low (400-1000 Kg/hectare) as opposed to a potential of 4,000 Kg per hectare. Farmers grow varieties of which no protein content is known. An experiment was carried out in Malawi to assess the productivity and protein content of 16 different soybean genotypes. The genotypes included the newly released ones: TG X 1830-20E, UG-5 and TG X 1908-8Fand those released earlier: Magoye, Nasoko, Makwacha, Ocepala-4, TGX 1937-1F, TG X 1954-1F, TGX 1485-1D, TGX 1019-2EB, TGX 1835-10E, TGX 1440-1E, TGX 1904-6F, TGX 1910- 13F, TGX 1910-14F. These genotypes were grown in plots of 5 meters by 4 meters each. The data was collected by field observations and lab experiments. The results showed that there was a significant genotypic improvement in some newly released varieties in terms of yield and other yield components. High grain yield and high number of branches per plant, number of pods per plant, podding height, harvest index, biological yield, dry matter content and 100 seeds weight were observed in the varieties TG X 1830-20E and UG-5. There was a significant difference (p<0.05) in yield per hectare and in protein content among the sixteen genotypes. Higher protein content was obtained in TGX 1830-20E, UG-5 and TG X 1908-8F than in the earlier approved ones. Among the genotypes, TGX 1830-20E, UG-5 and TGX 1908-8F were the most productive. The results showed that genotypes such as TGX 1485-1D had more protein content than those already released genotypes. The lowest protein content of 27.1% was found in Nasoko. Most of the newly released genotypes had the protein content ranging from 36% to 43%. The results on the newly released varieties have shown that genetic improvement in yield and protein content are possible through deliberate effort in plant breeding and so farmers can selectively grow varieties with the desired traits either for protein production or for non-protein (protein food) production. In addition, food producing industries can easily choose varieties based on the type of food product to be produced. The information should also help Researchers to know which varieties to be used when producing new varieties looking at specific traits whether yield traits or protein content.

Keywords
Soybean; genotype; productivity; protein content; traits; selection; variety; yield