Stability analysis for oil and protein content in soybean (Glycine max L. MERRIL) seed across varying environments

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Hampango, Mudenda
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University of Zambia
Soybean is an important crop with many important properties. The use of soybean varies from stock feed, biodiesel, edible oils and high protein food products, to soil amendment resulting from its nitrogen fixing ability and is a profitable cash crop. Zambia has a number of soybean varieties which have been developed with little consideration to adaptation for oil and protein to varying environments. Based on this, the stability of protein and oil content of soybean was evaluated across the three agro ecological zones of Zambia. The main objective of the study was to identify environments for high soybean oil and protein content production. Multi-location field trials involving fifteen soybean genotypes obtained from IITA, ZARI and SeedCo were conducted during the 2013/ 2014 rain season at five locations across the three agro ecological zones of Zambia namely; Masumba in Region I, Msekera, Kabwe and Golden Valley Agriculture Research Trust (GART) in Region II and Misamfu in Region III. A randomized complete block design with three replications was used at each site and the oil and protein content was determined using Near Infrared Reflectance. Analysis of variance (ANOVA) was used to determine statistical differences in performance of the genotypes for the studied traits while Additive Main Effect and Multiplicative Interaction (AMMI) Model was employed as a stability analysis tool. Results showed that both oil and protein content were significantly (p<0.05) affected by environments, genotypes and genotype by environment interactions, indicating differences in locations, presence of genetic variability among genotypes as well as the differential response of genotypes to environments. The mean oil content for the fifteen soybean genotypes ranged from 16.73% to 19.47% while the mean protein content ranged from 33.09% to 37.57%. In terms of locations, the highest mean oil content was obtained at Msekera (18.98%), while the lowest mean was from GART (16.38%). For protein content, the highest location mean was obtained from GART (38.23%) while the lowest was from Misamfu (33.47%). Msekera and GART can therefore be recommended for screening and production of genotypes with high oil and protein content respectively. AMMI indicated that the genotypes Lukanga, Safari, TGx 1988-22F and TGx 1740-2F were best suited for Msekera for high oil content while genotypes TGx 1830-20E, TGx 1987-23F, TGx 1887-65F and TGx 1988-22F were best suited for obtaining high protein content at GART. AMMI further indicated that TGx 1989-60F was the most stable genotype for oil content while for protein content, the genotypes TGx 1740-2F, Magoye and TGx 1988-18F were the most stable. These genotypes can be recommended for use as parental lines for developing soybean varieties that are stable for oil and protein content respectively.
MSc - Agriculture
Soybean , Soy oil