The study was carried out to understand the genetic basis for yield under drought environments,
and to map quantitative trait loci associated with yield and yield related components under drought
stress in sweetpotato. The sweetpotato BxT mapping population, generated from a cross between
sweetpotato varieties Beauregard and Tanzania was used for this study. Genotypes were evaluated
in irrigated and drought environments to evaluate the effect of drought on yield and yield related
parameters as well as genetic variability under drought conditions. Drought affected root yield,
foliage yield, biomass and harvest index at varying degrees, with highest relative yield reduction
in root yield. Drought tolerance indices were estimated based on root yield under drought and
irrigated conditions. Suitable drought tolerance indices identified were geometric mean
productivity, mean productivity and drought tolerance index. Genotypes were grouped as drought
tolerant and high yielding (DTHY), drought tolerant and low yielding (DTLY), drought
susceptible and high yielding (DSHY) and drought susceptible and low yielding (DSLY) based on
their root yield means. Drought also reduced chlorophyll content, leaf area, normalized difference
vegetation index (NDVI), photosynthetically active radiation, and increased canopy temperature.
Observed low heritability and non-significant variation among genotypes for physiological traits
indicates inefficiency of these traits for selection of drought tolerant genotypes in the BxT mapping
population. However, morphological traits had significant variability among genotypes, high to
moderate heritability under drought stress indicating they could be considered as potential
secondary traits for selection of drought tolerant genotypes. To understand the genetic basis of
drought tolerance in sweetpotato, QTLs associated with yield and yield related components under
irrigated, drought and rainfed conditions were mapped using the genotype by sequencing method,
GBSpoly. The occurrence of four QTLs on linkage group 9 in single environments and on linkage groups 11 and 6 for combined environments under only drought stressed conditions is indicative
of drought specific QTLs. With further studies, confirmation and validation of these QTLs may be
useful for drought tolerance-oriented breeding programmes in sweet potato.
CDR, C (2021). Genetic Studies And Qtl Mapping Of Drought Related Traits In A Sweetpotato (Ipomea Batatas(L.) Bi-Parental Mapping Population. Afribary.com: Retrieved April 16, 2021, from https://afribary.com/works/genetic-studies-and-qtl-mapping-of-drought-related-traits-in-a-sweetpotato-ipomea-batatas-l-bi-parental-mapping-population-1
Coalition, CDR. "Genetic Studies And Qtl Mapping Of Drought Related Traits In A Sweetpotato (Ipomea Batatas(L.) Bi-Parental Mapping Population" Afribary.com. Afribary.com, 08 Apr. 2021, https://afribary.com/works/genetic-studies-and-qtl-mapping-of-drought-related-traits-in-a-sweetpotato-ipomea-batatas-l-bi-parental-mapping-population-1 . Accessed 16 Apr. 2021.
Coalition, CDR. "Genetic Studies And Qtl Mapping Of Drought Related Traits In A Sweetpotato (Ipomea Batatas(L.) Bi-Parental Mapping Population". Afribary.com, Afribary.com, 08 Apr. 2021. Web. 16 Apr. 2021. < https://afribary.com/works/genetic-studies-and-qtl-mapping-of-drought-related-traits-in-a-sweetpotato-ipomea-batatas-l-bi-parental-mapping-population-1 >.
Coalition, CDR. "Genetic Studies And Qtl Mapping Of Drought Related Traits In A Sweetpotato (Ipomea Batatas(L.) Bi-Parental Mapping Population" Afribary.com (2021). Accessed April 16, 2021. https://afribary.com/works/genetic-studies-and-qtl-mapping-of-drought-related-traits-in-a-sweetpotato-ipomea-batatas-l-bi-parental-mapping-population-1