Combining ability of highland tropic adapted potato for tuber yield and yield components under drought

Abstract

Recurrent drought and late blight disease are the major factors limiting potato productivity in the northwest Ethiopian highlands. Incorporating drought tolerance and late blight resistance in the same genotypes will enable the development of cultivars with high and stable yield potential under erratic rainfall conditions. The objectives of this study were to assess combining ability effects and gene action for tuber yield and traits related to drought tolerance in the International Potato Centre’s (CIP’s) advanced clones from the late blight resistant breeding population B group ‘B3C2’ and to identify promising parents and families for cultivar development. Sixteen advanced clones from the late blight resistant breeding population were crossed in two sets using the North Carolina Design II. The resulting 32 families were evaluated together with five checks and 12 parental clones in a 7 x 7 lattice design with two water regimes and two replications. The experiment was carried out at Adet, in northwest Ethiopia under well-watered and water stressed conditions with terminal drought imposed from the tuber bulking stage. The results showed highly significant differences between families, checks, and parents for growth, physiological, and tuber yield related traits. Traits including marketable tuber yield, marketable tuber number, average tuber weight and groundcover were positively correlated with total tuber yield under both drought stressed and well-watered conditions. Plant height was correlated with yield only under drought stressed condition. GCA was more important than SCA for total tuber yield, marketable tuber yield, average tuber weight, plant height, groundcover, and chlorophyll content under stress. This study identified the parents with best GCA and the combinations with best SCA effects, for both tuber yield and drought tolerance related traits. The new population is shown to be a valuable genetic resource for variety selection and improvement of potato’s adaptation to the drought prone areas in northwest Ethiopia and similar environments.

Genetic combining ability of coriander genotypes for agronomic and phytochemical traits in response to contrasting irrigation regimes

“…The diallel mating design has been used to quantify the nature of gene action which control traits and also to estimate general combining ability (GCA) and specific combining ability (SCA) of parents and crosses, respectively. Examples of its use in a wide array of crops include those of Gao et al [ 28 ] in Agaricus bisporus , Townsend et al [ 29 ] in Artemisia annua , Zhang et al [ 30 ] in barley, Khodadadi et al [ 18 ] in coriander, dos Santos et al [ 31 ] in Theobroma cacao , Pereira et al [ 32 ] in cacao and Hirut et al [ 33 ] in potato. GCA is defined as the average yield of a parental genotype over relevant hybrids and corresponds to additive genetic effects, while the SCA is defined as the yield of a hybrid that deviates from what would be expected if traits were controlled by additive effects alone, i.e.…”

Effect of drought and waterlogging on saccharides and amino acids content in potato tubers

“…When drought occurs in spring and early summer, the quality and quantity of the tubers might be considerably reduced (Bündig et al 2017).Water stress influences potato growth and production by reducing the amount of productive foliage, by decreasing the rate of photosynthesis per unit of leaf area, and by shortening the vegetative growth period with respect to potato under well-watered conditions. Potato yield under water stress depends on the time, duration, and severity of the stress, as well as on genotype (Hirut et al 2017). Because a selection for water stress-tolerant genotypes in the field is time-consuming, cost-intensive and difficult to reproduce, it was proposed that screening…”

Potenciais genitores visando o melhoramento de batata para aparência de tubérculos e tolerância ao calor

“…Alguns autores relatam contribuição superior da CGC em relação à CEC para produtividade de tubérculos e caracteres relacionados. (TERRES et al, 2017;HIRUT et al, 2017;SILVA et al, 2013;BARBOSA;PINTO, 1998). Nos trabalhos de Kumar et al (2008), Galarreta et al, (2006) e Tai (1976 observa-se predominância da CEC nos caracteres de rendimento.…”