To understand the effect of heat stress on morphology and physiology of the cotton, eight cotton genotypes with their 15F1 hybrids (five lines, three testers) were grown in the field conditions under randomized complete block design (RCBD) with two treatments i.e. normal and hightemperature stresses with two replications followed by split-plot arrangement. Data were collected for biochemical and yield-related parameters. Mean values of all studied traits were reduced significantly under high-temperature stress whilst the mean value of lint%, catalase activity, total soluble proteins, peroxidase, and carotenoids were increased under high-temperature. Under both conditions, the number of bolls, boll weight, seed cotton yield, lint index, seed mass per boll, hydrogen peroxide content, catalase activity, total soluble proteins, carotenoids, and chlorophyll contents had high heritability values along with high genetic advance percent mean which revealed, these traits were controlled by additive gene action. The lint%, seed index, short fiber index, fiber strength, fiber fineness, upper half mean length and peroxidase activity had high heritability with moderate genetic advance under heat stress conditions which showed, these traits were controlled by non-additive gene action. Under both temperature conditions, FH-458, IUB-65, CRS-2, and FH-313 were good general combiners for physicochemical and yield-related traits. The cross combination of IUB-013× CRS-2 and FH-458× FH-313 were good specific combiner for plant height and seed cotton yield whilst for fiber quality and biochemical traits, the best specific combiners were VH-329× FH-313 and IUB-013× CRS-2. These identified parents and cross combinations might be used for improving already present commercial varieties under high-temperature stress.

No abstract

Background Cotton (Gossypium hirsutum L.) is grown for fiber and oil purposes in tropical and sub-tropical areas of the world. Pakistan is the 4th largest producer of cotton. It has a significant contribution in the GDP of Pakistan. Therefore, the present study was performed to assess the genetic variations and genetic diversity of yield and fiber quality traits in cotton and to analyze the associations present among them. Results Analysis of variance exhibited significant variation for all studied traits except total number of nodes and the height to node ratio. The phenotypic coefficient of variation was higher than the genotypic coefficient of variation for all studied traits. Plant height, monopodial branches, total number of bolls, lint index, seed index, and seed cotton yield displayed high heritabilities in a broad sense with maximum genetic advance. Correlation analysis revealed that seed cotton yield had a significant positive association with plant height, the number of monopodial branches, the number of sympodial branches, ginning outturn (GOT), the number of bolls, seed per boll, seed index, uniformity index, the number of sympodial branches, reflectance, and seed index at the genotypic level while a significant positive relationship was observed with plant height, the number of sympodial branches, boll number, and GOT. Plant height, monopodial branches, GOT, boll weight, seeds per boll, and short fiber index exerted direct positive effects on seed cotton yield. The first 6 principal component analysis (PCs) out of the total fourteen PCs displayed eigenvalues (> 1) and had maximum share to total variability (82.79%). The attributes that had maximum share to total divergence included plant height, uniformity index, the number of sympodial branches, seed per boll, GOT, seed cotton yield, and short fiber index. Conclusion The genotype AA-802, IUB-13, FH-159, FH-458, and CIM-595 were genetically diverse for most of the yield and fiber quality traits and could be utilized for the selection of better performing genotypes for further improvement.

This study was conducted through the seasons of 2013 and 2014 to determine the optimum bud loads/ vine for Autumn Royal seedless "grapevines. Three years old uniform vines were uniform chosen and pruned to four levels of bud load, namely (32, 42, 52 and 60 buds/ vine). With fruiting spur at 2, 3 and 4 buds per spurThe results showed that the percentage of bursted buds was decreased significantly by increasing bud load /vine in the two seasons of the study. Data also indicated that 42 buds/ vine were more suitable for Autumn Royal seedless grapevines to produce good yield and fruit quality. On the other hand, 32 buds/vine or 60 buds/vine were unfavorable science it produced rather clusters.In addition, pruning Autumn Royal seedless "grapevines to 42buds /vine by leaving 21 spur with 2 eyes/spur or leaving 14 spur with 3 eyes per spur resulted a high yield and good quality, reduced cluster compactness and reduced shoot berries %, gave the greatest cluster weight, berry firmness, adherence, T.S.S and anthocyanin content. Increasing bud load increased number of cluster/vine and yield but reduced cluster weight. Vines pruned to 32 buds / vine gave the greatest C/N ratio of the canes. Whereas vines pruned to 60 buds / vine showed higher percent of T.A than the other levels of bud load and cane length.

No abstract