Genotypic variability for root/shoot parameters under water stress in some advanced lines of cotton (Gossypium hirsutum L.)

Abstract

ABSTRACT. Research pertaining to genetic variability parameters, heritability, and genotypic, phenotypic, simple, and environmental correlations for various seedling traits in five elite advanced cotton (Gossypium hirsutum L.) lines (FH-113, FH-114, FH-941, FH-942, and FH-2015) and one check (CIM-496) was carried out during October and November 2010 under greenhouse conditions at the Cotton Research Institute (Faisalabad, Pakistan). Material was raised in plastic tubes with a randomized complete block design replicated three times. Three drought shocks were applied by withholding water from the tube-sown plants for 8-, 10-, and 12-day intervals. After 60 days of sowing, data on root/shoot traits like root length (cm), shoot length (cm), root weight (g), shoot fresh weight (g), lateral root number, root dry weight (g) shoot dry weight (g), and total plant weight (g) were recorded. Considerable genotypic variations existed between genotypes for all seedling characters. Higher broad-sense heritability estimates were found for all traits studied. Maximum broad- Genotypic variability of Gossypium hirsutum sense heritability coupled with high genetic advance in root length (0.99, 17.34), lateral root number (0.91, 2.89), and shoot length (0.90, 4.35) suggested a potential for genetic improvement through breeding and selection. The correlation coefficients among root length, shoot length, root dry weight, fresh shoot weight, and total plant weight were positively and significantly correlated; thus, they can be selected simultaneously as drought tolerance selection indexes owing to the absence of undesired relationships. Genotypes FH-942 and FH-113 had the lowest excised leaf water loss during the first 4 h and also for the next 4 h. Therefore, these two advanced lines with high initial water content and lower excised leaf water loss had better adaptation to water stress.

Screening of Sesbania accessions based on seed germination and seedling biomass

“…These differences may be due to the genetic make-up of collected Sesbania accessions (Joshi-Saha and Gopalakrishna, 2007; Sarwar et al, 2015). Riaz et al (2013) observed similar result in cotton germplasms and found significant variability among genotypes. Accession #26, 45, 47, 93, 97, 98, 101, 102, 116 120, 121 and 122 were performed better in terms of seedling vigour index (above 1440) (data not shown here).…”

Mapping QTLs for drought tolerance in an F2:3 population from an inter-specific cross between Gossypium tomentosum and Gossypium hirsutum

“…As reported earlier by MacCaughey (1917), G. tomentosum has xerophytic features such as deep root penetration and it is endemic to the dry coastal regions of Hawaii. The importance of root length for drought tolerance in cotton has previously been established (Riaz et al, 2013). Therefore, further research should focus on examining the root growth parameters of cotton under drought conditions and compare them with those of upland cultivated cotton.…”

“…The final linkage map consisted of 1295 markers that amplified 1342 loci (Tables S1 and S2). A complete cotton chromosome assignment for this map was done based on the previously chromosome-anchored map (Riaz et al, 2013).…”

Genetic gains from selection for fiber traits in Gossypium hirsutum L.

“…Ali et al (2008) studied the fiber quality in G. hirsutum L. and reported that the additive variance would be significant for all evaluated traits and relatively less than the dominance for length, resistance, fineness, uniformity, and elongation. Riaz et al (2013) conducted studies on various features of the five elite cotton lines of G. hirsutum. They recorded considerable genotypic variation among the genotypes and heritability estimates in the broad sense for all evaluated traits.…”