Browsing by Author "Kawuki, R."

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    Adaptation and stability of vegetable soybean genotypes in Uganda
    (African Crop Science Journal, 2019-05-17) Tsindi, A.; Kawuki, R.; Tukamuhabwa,P.
    Vegetable soybean (Glycine max L. Merr.) is a specialty soybean, harvested as a vegetable when seeds are immature (R6 stage) and have expanded to fill 80 to 90% of the pod. The objective of the study was to assess the adaptation and stability of vegetable soybean genotypes in different agro-ecological zones of Uganda to enable selection of genotypes. A total of 21 genotypes were planted in Uganda for two consecutive seasons. Genotypes PI615437-B had the highest number of pods, while AGS 329 matured earliest in 64 days. Only AGS 292, AGS 329 and AGS 338 had 100 seeds weight above 30 g. G10427 was the ideal genotype in terms of adaptation and stability for fresh seed yield, with mean yield of 4281kg ha-1; followed by G2843 with 4039 kg ha-1. PI615437-B came third with fresh seed yield of 4024 kg ha-1. The least stable and adapted genotype was AGS 329 with only 1609 kg ha-1. Nakabango 1 and MUARIK 1 were the ideal environments, which were the most discriminative and representative. We recommend that G10427 be used as a test genotype and for improvement to produce a variety with good attributes, especially large seed, high yield and adaptable to Uganda.
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    Fruit Set and Plant Regeneration in Cassava Following Inter specific Pollination with Castor Bean
    (African Crop Science Journal, 2019) Baguma, J.K.; Mukasa, S.B.; Kawuki, R.; Tugume, A.K.; Buttibwa, M.; Nalela, P.; Eyokia, M.; Oshaba, B.; Ceballos, H.; Lentini, Z.; Baguma, Y.
    The increasing demand for cassava (Manihot esculenta Crantz) for food and non-food uses in the tropics necessitates that its breeding for increased root productivity be made faster. The characteristic long breeding cycle and heterozygous nature of this crop, pose a major obstacle to its rapid genetic improvement. This study aimed at inter-pollinating cassava with castor bean (Ricinus communis), with a purpose of inducing and regenerating cassava doubled haploids (DHs). A total of 3,349 flowers from twelve elite cassava varieties were inter-pollinated with caster bean. A total of 803 fruits were harvested for early embryo rescue and/or ovule culture. Of these, three were dissected to obtain seven unique embryos, while 800 were dissected to obtain 1312 young ovules, all of which were cultured in vitro. Overall, 82 (6.25%) of the cultured ovules formed callus that originated from the embryosac region, which is haploid. Four out of seven rescued embryos (57.1%) regenerated into plantlets. Ploidy analyses of 24 samples using flow cytometry revealed that 23 of the analysed samples were diploid. However, one callus sample was anueploid. Only one sample had an exceptionally high level of homozygosity ( 84.2%). These findings lay a foundation for future research aimed at induction of haploids in cassava.