Rukundo Placide, Shimelis Hussein, Laing Mark, Gahakwa Daphrose
African Centre for Crop Improvement, University of KwaZulu-NatalPietermaritzburg, South Africa; Rwanda Agriculture Board, HorticultureKigali, Rwanda.
African Centre for Crop Improvement, University of KwaZulu-Natal Pietermaritzburg, South Africa.
Front Plant Sci. 2017 Jan 10;7:1981. doi: 10.3389/fpls.2016.01981. eCollection 2016.
Knowledge on gene action and trait expression are important for effective breeding. The objective of this study was to determine the general combining ability (GCA), specific combining ability (SCA), maternal effects and heritability of drought tolerance, yield and yield components of candidate sweetpotato clones. Twelve genotypes selected for their high yield, dry matter content or drought tolerance were crossed using a full diallel mating design. Families were field evaluated at Masoro, Karama, and Rubona Research Stations of Rwanda Agriculture Board. Success rate of crosses varied from 1.8 to 62.5% with a mean of 18.8%. Family by site interaction had significant effect ( < 0.01) on storage root and vine yields, total biomass and dry matter content of storage roots. The family effects were significant ( < 0.01) for all parameters measured. Broad sense heritability estimates were 0.95, 0.84, 0.68, 0.47, 0.74, 0.75, 0.50, and 0.58 for canopy temperature (CT), canopy wilting (CW), root yield, skin color, flesh color, dry matter content, vine yield and total biomass, respectively. The GCA effects of parents and SCA effects of crosses were significant ( < 0.01) for CT, CW, storage root, vine and biomass yields, and dry matter content of storage root. The ratio of GCA/SCA effects for CT, CW, yield of storage roots and dry matter content of storage roots were higher than 50%, suggesting the preponderance of additive over non-additive gene action in the expression of these traits. Maternal effects were significant ( < 0.05) among families for CT, CW, flesh color and dry matter content, vine yield and total biomass. Across sites, the best five selected families with significant SCA effects for storage root yield were, Nsasagatebo × Otada 24, Otada 24 × Ukerewe, 4-160 × Nsasagatebo, K513261 × 2005-034 and Ukerewe × K513261 with 11.0, 9.7, 9.3, 9.2, 8.6 t/ha, respectively. The selected families are valuable genetic resources for sweetpotato breeding for drought tolerance, yield and yield components in Rwanda or similar environments.
了解基因作用和性状表达对于有效的育种至关重要。本研究的目的是确定候选甘薯无性系耐旱性、产量及产量构成因素的一般配合力（GCA）、特殊配合力（SCA）、母体效应和遗传力。选用12个因高产、干物质含量高或耐旱性强而挑选出的基因型，采用完全双列杂交设计进行杂交。在卢旺达农业委员会的马索罗、卡拉马和鲁博纳研究站对各家系进行田间评估。杂交成功率从1.8%到62.5%不等，平均为18.8%。家系与地点的互作对贮藏根产量、藤蔓产量、总生物量和贮藏根干物质含量有显著影响（<0.01）。所测的所有参数的家系效应均显著（<0.01）。冠层温度（CT）、冠层萎蔫（CW）、根产量、皮色、肉色、干物质含量、藤蔓产量和总生物量的广义遗传力估计值分别为0.95、0.84、0.68、0.47、0.74、0.75、0.50和0.58。亲本的GCA效应和杂交组合的SCA效应在CT、CW、贮藏根、藤蔓和生物量产量以及贮藏根干物质含量方面均显著（<0.01）。CT、CW、贮藏根产量和贮藏根干物质含量的GCA/SCA效应比值高于50%，表明在这些性状的表达中，加性基因作用比非加性基因作用占优势。家系间在CT、CW、肉色和干物质含量、藤蔓产量和总生物量方面的母体效应显著（<0.05）。在各地点中，贮藏根产量具有显著SCA效应的最佳五个入选家系分别是Nsasagatebo×Otada 24、Otada 24×Ukerewe、4 - 160×Nsasagatebo、K513261×2005 - 034和Ukerewe×K513261，产量分别为11.0、9.7、9.3、9.2、8.6吨/公顷。这些入选家系是卢旺达或类似环境下甘薯耐旱性、产量及产量构成因素育种的宝贵遗传资源。
