Heterosis and inbreeding depression for yield and oil traits of sunflower genotypes under water stress conditions

The mean squares from analysis indicated significant differences was observed between treatments, inbred parents, F1 hybrids and F2 progenies for agronomic, oil and protein traits. The noteworthy variances between parents vs. hybrids indicated the importance of heterosis breeding. heterotic effects were found as potential hybrids for earliness, seed yield, oil and protein content in both the environments. The hybrids such as Thatta × UC-666, Mehran × Peshawar-93 and HO.1 × B-2 which have articulated high hybrid vigor in F1s for majority of the traits in normal and adverse conditions may be recommended for further commercial exploitation. The F2 progenies manifested high inbreeding depression for phenological traits and plant height signified that earlier maturing and dwarf plants resistant to lodging can achieved from filial generations

Assessment of wheat cultivars for drought tolerance via osmotic stress imposed at early seedling growth stages

A study was conducted in the Department of Plant Breeding and Genetics,Sindh Agriculture University, Tandojam, Pakistan during the year 2009. Sixteen spring wheat cultivars (Triticum aestivum L.) were screened under osmotic stress with three treatments i.e. control-no PEG (polyethylene glycol), 15 percent and 25 percent PEG-6000 solution. The analysis of variance indicated significant differences among treatments for all seedling traits except seed germination percentage. Varieties also differed significantly in germination percentage, coleoptile length, shoot root length, shoot weight, root/shoot ratio and seed vigour index. However, shoot and root weights were non-significant. Significant interactions revealed that cultivars responded variably to osmotic stress treatments; hence provided better opportunity to select drought tolerant cultivars at seedling growth stages. The relative decrease over averages due to osmotic stress was 0.8 percent in seed germination, 53 percent in coleoptile length 62.9 percent in shoot length, 74.4 percent in root length, 50.6 percent in shoot weight, 45.1 percent in root weight, 30.2 percent in root/shoot ratio and 68.5 percent in seed vigour index. However, relative decrease of individual variety for various seedling traits could be more meaningful which indicated that cultivar TD-1 showed no reduction in coleoptile length, while minimum decline was noted in Anmol. For shoot length, cultivar Sarsabz expressed minimum reduction followed by Anmol. However, cultivars Anmol, Moomal, Inqalab-91, and Pavan gave almost equally lower reductions for root length suggesting their higher stress tolerance. In other words, cultivars Anmol, Moomal, Inqalab-91, Sarsabz, TD-1, ZA-77 and Pavan had relatively longer coleoptiles, shoots and roots, and were regarded as drought tolerant. Correlation coefficients among seedlings traits were significant and positive for all traits except germination percentage which had no significant correlation with any of other trait. The results indicated that increase in one trait may cause simultaneous increase in other traits; hence selection for any of these seedling attributes will lead to develop drought tolerant wheat cultivars

Profiling dehydrin gene sequence and physiological parameters in drought tolerant and susceptible spring wheat cultivars.

Physiological and yield traits such as stomatal conductance (mmol m-2s-1), Leaf relative water content (RWC %) and grain yield per plant were studied in a separate experiment. Results revealed that five out of sixteen cultivars viz. Anmol, Moomal, Sarsabz, Bhitai and Pavan, appeared to be relatively more drought tolerant. Based on morphophysiological results, studies were continued to look at these cultivars for drought tolerance at molecular level. Initially, four well recognized primers for dehydrin genes (DHNs) responsible for drought induction in T. durum L., T. aestivum L. and O. sativa L. were used for profiling gene sequence of sixteen wheat cultivars. The primers amplified the DHN genes variably like Primer WDHN13 (T. aestivum L.) amplified the DHN gene in only seven cultivars whereas primer TdDHN15 (T. durum L.) amplified all the sixteen cultivars with even different DNA banding patterns some showing second weaker DNA bands. Third primer TdDHN16 (T. durum L.) has shown entirely different PCR amplification prototype, specially showing two strong DNA bands while fourth primer RAB16C (O. sativa L.) failed to amplify DHN gene in any of the cultivars. Examination of DNA sequences revealed several interesting features. First, it identified the two exon/one intron structure of this gene (complete sequences were not shown), a feature not previously described in the two database cDNA sequences available from T. aestivum L. (gi|21850). Secondly, the analysis identified several single nucleotide polymorphisms (SNPs), positions in gene sequence. Although complete gene sequence was not obtained for all the cultivars, yet there were a total of 38 variable positions in exonic (coding region) sequence, from a total gene length of 453 nucleotides. Matrix of SNP shows these 37 positions with individual sequence at positions given for each of the 14 cultivars (sequence of two cultivars was not obtained) included in this analysis. It demonstrated a considerable diversity for this gene with only three cultivars i.e. TJ-83, Marvi and TD-1 being similar to the consensus sequence. All other cultivars showed a unique combination of SNPs. In order to prove a functional link between these polymorphisms and drought tolerance in wheat, it would be necessary to conduct a more detailed study involving directed mutation of this gene and DHN gene expression

Evaluating spring wheat cultivars for drought tolerance through yield and physiological parameters at booting and anthesis

Progress in wheat yields under drought conditions is rather a difficult task to achieve. The experiment was conducted in factorial design with 16 spring wheat cultivars grown under two irrigation regimes, non-stress and water-stress imposed at boot and anthesis growth stages. Water-stress significantly influenced the physiological and yield traits in both the growth stages, yet the reductions in most traits were pronounced at anthesis than at boot. Stomatal conductance, relative water content, leaf area (LA), seeds/spike, 1000-grain weight and grain yield/plant were the best drought tolerant indicators. On the basis of physiological and yield traits, the cultivars Moomal, Bhitai, TD-1, and Abadgar proved to be the best performing in water-stress conditions. Stomatal conductance, RWC% and LA were significantly and positively correlated with grain yield/plant. These results suggest that the stomatal conductance, relative water content and leaf area are the most important traits that should be considered while developing drought tolerant wheat genotypes.Keywords: Water stress, boot and anthesis, yield and physiological traits, wheat genotype

Line × Tester Analysis for Earliness Yield and Yield Contributing Traits in Gossypium hirsutum L.

The present study was carried out at Agriculture Research Institute (ARI) Tando Jam during 2016. The experimental material consisted of six lines viz., CRIS-134, Sindh-1, Sadori, Malmal, IR-901 and three testers; Bt-3701, Bt-121 and CIM-534.The crosses were made in line × tester mating design. F1 hybrids along with parents were sown in Randomized Complete Block Design with four replications in 2016. Seven yield and early maturing traits was recorded like, days to 1st flowering, days to 75% boll opening, plant height(cm), sympodial branches plant-1, bolls plant-1, seed cotton yield-1(g) and lint (%) for estimating of combining ability. The analysis of variance showed that genotypes, crosses, parents, parent vs crosses, lines, testers and line × tester were significant which demonstrated that genetic difference were present in genotypes for various yield and early maturing parameters. Among the lines, Sindh-1, CRIS-134 and testers, Bt-121 and Bt-3701 were best combiners and F1 hybrids like CRIS-134 × Bt-3701, Malmal × Bt-3701, CRIS-134 × Bt-121 were best combiners for all characters

Line × Tester Analysis for Earliness Yield and Yield Contributing Traits in Gossypium hirsutum L.

The present study was carried out at Agriculture Research Institute (ARI) Tando Jam during 2016. The experimental material consisted of six lines viz., CRIS-134, Sindh-1, Sadori, Malmal, IR-901 and three testers; Bt-3701, Bt-121 and CIM-534.The crosses were made in line × tester mating design. F1 hybrids along with parents were sown in Randomized Complete Block Design with four replications in 2016. Seven yield and early maturing traits was recorded like, days to 1st flowering, days to 75% boll opening, plant height(cm), sympodial branches plant-1, bolls plant-1, seed cotton yield-1(g) and lint (%) for estimating of combining ability. The analysis of variance showed that genotypes, crosses, parents, parent vs crosses, lines, testers and line × tester were significant which demonstrated that genetic difference were present in genotypes for various yield and early maturing parameters. Among the lines, Sindh-1, CRIS-134 and testers, Bt-121 and Bt-3701 were best combiners and F1 hybrids like CRIS-134 × Bt-3701, Malmal × Bt-3701, CRIS-134 × Bt-121 were best combiners for all characters

Characterization of Elite Upland Cotton Genotypes for Earliness and Yield Traits

Short duration cotton genotypes increased the chances to harvest crop before cold and rainy weather conditions. However, earliness in cotton is a difficult character, which is assessed by determining many plant traits. The current experimental was conducted at Cotton Section, A.R.I. Tando Jam, during kharif season 2013. The eight cotton genotypes including CRIS-342, Sindh-I, Haridost, Malmal, Bt-121, Bt-3701, TS-501 and Shahbaz were sown i n randomized complete block design with four replications. In a total, seven quantitative traits were measured such as days to first flowering, node number to set first sympodial branch, node number to set first flowering, sympodial branch length (cm), sympodial branches plant-1, number of bolls plant-1, seed cotton yield plant-1(g). The mean squares from analysis of variances showed that genotypes differed significant (P 0.01) for all the studied traits, demonstrating a vast genetic variability in tested genotypes. The genotypes, Sindh-1, CRIS-342, Bt-121 and Bt-3701 were characterized as early maturing or short duration cotton varieties. However, the correlation between yield and earliness traits were best criteria for developing the short duration cotton yield varieties

Characterization of Elite Upland Cotton Genotypes for Earliness and Yield Traits

Short duration cotton genotypes increased the chances to harvest crop before cold and rainy weather conditions. However, earliness in cotton is a difficult character, which is assessed by determining many plant traits. The current experimental was conducted at Cotton Section, A.R.I. Tando Jam, during kharif season 2013. The eight cotton genotypes including CRIS-342, Sindh-I, Haridost, Malmal, Bt-121, Bt-3701, TS-501 and Shahbaz were sown i n randomized complete block design with four replications. In a total, seven quantitative traits were measured such as days to first flowering, node number to set first sympodial branch, node number to set first flowering, sympodial branch length (cm), sympodial branches plant-1, number of bolls plant-1, seed cotton yield plant-1(g). The mean squares from analysis of variances showed that genotypes differed significant (P 0.01) for all the studied traits, demonstrating a vast genetic variability in tested genotypes. The genotypes, Sindh-1, CRIS-342, Bt-121 and Bt-3701 were characterized as early maturing or short duration cotton varieties. However, the correlation between yield and earliness traits were best criteria for developing the short duration cotton yield varieties

Optimizing the phosphorus use in cotton by using CSM-CROPGRO-cotton model for semi-arid climate of Vehari-Punjab, Pakistan

Crop nutrient management is an essential component of any cropping system. With increasing concerns over environmental protection, improvement in fertilizer use efficiencies has become a prime goal in global agriculture system. Phosphorus (P) is one of the most important nutrients, and strategies are required to optimize its use in important arable crops like cotton (Gossypium hirsutum L.) that has great significance. Sustainable P use in crop production could significantly avoid environmental hazards resulting from over-P fertilization. Crop growth modeling has emerged as an effective tool to assess and predict the optimal nutrient requirements for different crops. In present study, Decision Support System for Agro-technology Transfer (DSSAT) sub-model CSM-CROPGRO-Cotton-P was evaluated to estimate the observed and simulated P use in two cotton cultivars grown at three P application rates under the semi-arid climate of southern Punjab, Pakistan. The results revealed that both the cultivars performed best at medium rate of P application (57\ua0kg\ua0ha-1) in terms of days to anthesis, days to maturity, seed cotton yield, total dry matter production, and harvest index during 2013 and 2014. Cultivar FH-142 performed better than MNH-886 in terms of different yield components. There was a good agreement between observed and simulated days to anthesis (0 to 1\ua0day), days to maturity (0 to 2\ua0days), seed cotton yield, total dry matter, and harvest index with an error of -4.4 to 15%, 12-7.5%, and 13-9.5% in MNH-886 and for FH-142, 4-16%, 19-11%, and 16-8.3% for growing years 2013 and 2014, respectively. CROPGRO-Cotton-P would be a useful tool to forecast cotton yield under different levels of P in cotton production system of the semi-arid climate of Southern Punjab