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Cowpea, in addition to being a food and feed crop, plays a key role in sustainable farming. The present study’s goal is to develop new high-yielding cowpea varieties. A Field experiment was carried out across 3 summer seasons and the breeding program included 28 distinct cowpea varieties, out of which five potential parents were selected for this investigation. Local cultivars, i.e., Cream 7 ‘Cr7’, Dokki 331 ‘D331’, Commercial 1 ‘Com1’, and introduced cultivars, i.e., Colossus ‘Col’ and Asian Introduction ‘AI’ were utilized to produce six crosses in two generations apart; F 1 and F 2 : Col x AI, Col x Com1, Cr7 x AI, Cr7 x Com1, D331 x AI, and D331 x Com1. ‘AI’ and ‘Com1’ were superior in pod length, pod diameter, number of seeds/pod and seeds weight/pod, whereas ‘Col’, ‘Cr7’ and ‘D331’ were superior in seeds yield/plant, number of pods/plant and the least number of aborted ovules/pod. The genotypes/crosses showed greater genotypic variance (GV) than phenotypic variance (PV) for number of pods/plant, pod length, number of seeds/pod, number of aborted ovules/pod, fresh pod weight, seeds weight/pod, and seeds yield/plant. All studied variables showed high heritability (H%) in genotypes/crosses, despite the exception of seeds weight/pod, which ranged from 29.14 in ‘D331’ to 83.7 in F 2 of Col x Com1. F 2 plants and their parents’ genotypes showed greater H%. Cr7 x AI developed the most H%, 99.04% for number of pods/plant. D331 x Com1 and Cr7 x AI exhibited moderate H% for fresh pod weight in F 1 , but all other crosses had high H%. F 1 and F 2 crosses yielded moderate to high GCV and PCV for number of seeds/pod. Variations in parental genotypes and crossings reflect genetic diversity and the possibility of selection. Crossing with ‘AI,’ and ‘Com1’ genotypes enhanced the performance of the other varieties, ‘Col’, ‘D331’ and ‘Cr7’. Cr7 x Com1 and D331 x AI were selected as the most promising crosses for cowpea breeding programs.

Information on the extent of genetic variability and association among quantitative traits are vital for any crop improvement program and the development of suitable selection strategies. Limited research has been carried out thus far on potato genetic variability and trait association. This study on genetic variability and association among quantitative traits was conducted to assess the extent of genetic variability among yield and agronomic traits to identify superior varieties for the breeding program. To this effect, 20 improved varieties and a local cultivar were planted at two locations in central Ethiopia during the main cropping season of 2017/18 in a randomized complete block design using three replications. Analysis of variance of tuber yield and yield traits at each location and over locations, revealed the existence of highly significant ( P < 0.01) differences among varieties in all agronomic and yield traits. Phenotypic coefficient of variation values ranged from 0.75% (specific gravity) to 32.22% (total starch yield) while the genotypic coefficient of variation values ranged between 0.70% (specific gravity) to 30.22% (total starch yield). Maximum difference between phenotypic and genotypic coefficient of variation values were noted for stem number, average tuber number, average tuber weight, number of leaves per plant and tuber yield. Hence, these traits are substantially influenced by the physiological status of the seed tuber at planting and by the environment, post emergence. Range of variability for most of the traits was high, indicating ample scope for selection and improvement in these traits. The estimated values for broad sense heritability and genetic advance, as percent of mean, ranged from 33.52% to 98.66% and 1.35% to 58.26%, respectively. All the traits had high heritability values, except average tuber number per hill, days to physiological maturity, average tuber weight and number of leaves per plant with moderate heritability values.

Salt stress is one of the major limitations to modern agriculture that negatively influences plant growth and productivity. Salt tolerant cultivar can provide excellent solution to enhance stress tolerance with plant fitness to unfavorable environments. Therefore, this study was aimed to screen salt tolerant sorghum genotypes through evaluating of different morphological, biochemical, and physiological attributes in response to salinity stress. In this study, we have been evaluated total six sorghum genotypes including Hybrid sorgo, Debgiri, BD-703, BD-706, BD-707, and BD-725 under salt stress (12 dS m−1 NaCl). The response variables included length and weight of root and shoot, root: shoot ratio (RSR), photosynthesis (A), transpiration rate (E), elemental concentrations (K+ , Na+ and K+ /Na+ ), photochemical efficiency of photosystem II (Fv/Fm), water use efficiency (WUE) and pigment content (chlorophyll a, and b). The results revealed that saline environment significantly reduced all response variables under study of sorghum genotypes, however, Hybrid sorgo remained unmatched by recording the maximum root and shoot traits. The same genotype recorded higher photosynthetic efficiency which was attributed to Na+ extrusion, K+ uptake and higher K+ /Na+ ratio (1.8 at stress), while these mechanisms were not fully active in rest of genotypes. Moreover, this study also implies the involvement of proline in imparting tolerance against saline environment in Hybrid sorgo genotype. Overall, BD-703 remained the most salt sensitive genotype as evident from the minimum morphological growth traits and the least biosynthesis of osmoprotectants. These findings open new research avenues for salt stress alleviation by identifying elite salt-tolerant genotypes of sorghum for breeding programs.

Genetic variation in cotton is crucial when traits are heritable and elucidation of the underlying genetic components of these helps in selecting elite genotypes. A research was done to determine broad-sense heritability of traits through variance components in different cotton genotypes. The trials were laid out in randomized complete design with three replications. Ten cotton genotypes were used in the study. The results revealed highly significant differences among genotypes on all the characteristics. The experimental lines 917-05-7 had the highest yield (1919 kg/ha), the biggest bolls (6.33 g), produced more lint (853.9 kg/ha), and had taller plants (123.9 cm). Significant genotype by environmental interactions were detected which caused low heritability values, low error variance, and low genotype by environment variances, which allowed easier selection of genotypes. Further partitioning of the genotype by environment effects revealed the most stable and highly performing genotypes and these were 907-05-9 and TN96-05-9 which were concluded to be the best performing cotton lines.

Genetic variability, correlation, path coefficient analysis and test of normality was conducted in an F sub(8) recombinant inbred aerobic rice population developed by single seed descent method to evaluate its potential as a mapping population. Estimates of genotypic variance, phenotypic variance, genotypic coefficient of variance (GCV), phenotypic coefficient of variance (PCV), heritability in the broad sense (H) and expected genetic advance at 5% selection index (GA) for grain yield and other attributing characters were computed. In all the cases, PCV was higher than GCV indicating the influence of environment on the characters. High heritability coupled with high GA was observed for several plant traits; number of tillers, plant height, total number of spikelets panicle super(-1), biomass plant super(-1), straw weight, harvest index and grain yield plant super(-1) and hence offered good scope for selection. Grain yield plant super(-1 )was found to be positively correlated with plant height, number of tillers, panicle length, panicle exsertion, number of panicles plant super(-1), single panicle weight, test weight, number of fertile spikelets panicle super(-1), straw weight, biomass plant super(-1), harvest index and grain breadth both at genotypic and phenotypic levels. Harvest index exerted maximum positive direct effect, followed by biomass plant super(-1) and straw weight on grain yield plant super(-1) at phenotypic level. Shapiro-Wilks 'W test of normality' indicated that the population was skewed towards female parent IR50 for some traits and for some others towards Moroberekan, the male parent. Most of the characters that showed skewness were platykurtic with a kurtosis value of less than 3.

Rubber dandelion (Taraxacum kok-saghyz or TK) is a potential industrial crop species that can produce high-quality natural rubber in its roots. The present study estimated trait variance, inter-trait correlation, and entry-mean heritability for rubber yield-related traits and analyzed associations between these traits and 42 single-nucleotide polymorphism (SNP) markers. A trial was conducted at three environments to assess a biparental progeny of 66 F1 full-sibs, in a randomized complete block design (RCBD) with two replicates. Significant correlations, broad ranges of variation, and significant genotypic variance components were identified for five measured phenotypic traits. Moderate broad-sense heritability on an entry-mean heritability estimates (0.51–0.61) were obtained for five rubber yield-related traits based on a 1-year trial. However, the broad-sense heritability in general sense ranged from 0.09 to 0.15 depending on the trait. Two linkage groups were identified. Association analysis identified seven significant marker-trait gene associations, and only one marker was related to two traits. The implications of trait correlations and heritability for selection and improvement are discussed.

The wide range of climatic condition in the natural distribution of chir pine is expected to result in high genetic variation within different populations of the species. The present study on the provenance variation of chir pine aims to determine the nature and extent of variation in wide range of populations with respect to 23 morphological traits of cone, seed and seedling, (at nursery stage) of 63 provenances of Pinus roxburghii. Seed sources exhibited a wide range of variability in terms of mean vales for various traits, standard deviation, variance, coefficient of variability, broad sense heritability, genetic advance and genetic gain and offer ample scope for undertaking screening for the desired traits. Genotypic variance (V ) and genotypic coefficient of variability (GCV) for most of the parameters were found to be higher than corresponding environmental variance (V ) and environmental coefficient of variability (ECV), except cone fresh weight, survival%, days taken for bud break and collar diameter where V and ECV dominated the V and GCV, thus indicating influence of environment on the expression of these traits. Moderate to high percentage of heritability coupled with same intensity of gain, was observed for many of the traits studied under laboratory conditions and at nursery stage e.g. for germination percentage, MGT, GV. This signifies that these traits are under strong genetic control and good amount of heritable additive genetic component can be exploited for further selection and improvement of this species.

Background Photosynthate partitioning and within-plant boll distribution play an important role in yield formation of cotton; however, if and how they interact to mediate yield remains unclear. The objective of this study was to investigate the genotypic variance in photosynthate partitioning and within-plant boll distribution, with a focus on their interactions with regard to yield and yield components. A field experiment was conducted in the Yellow River region in China in 2017 and 2018 using a randomized complete block design with three replicates. Photosynthate partitioning of three commercial cultivars (DP 99B, Lumianyan 21 and Jimian 169), varying in yield potential, to different organs (including bolls) at early flowering, peak flowering, and peak boll-setting stages, as well as within-plant boll distribution at harvest, and their effects on yield formation were examined. Results Lint yield of Jimian 169 was the highest, followed by Lumianyan 21 and DP 99B. Similar differences were observed in the number of inner bolls and boll weight among the three cultivars. J169 partitioned significantly more photosynthate to the fruit and fiber than Lumianyan 21 and DP 99B and allocated over 80% of assimilates to the inner bolls. Additionally, Lumianyan 21 allocated a higher proportion of photosynthate to bolls and fiber, with 12.5%–17.6% more assimilates observed in the inner bolls, than DP 99B. Conclusions Genotypic variance in lint yield can be attributed to differences in the number of inner bolls and boll weight, which are affected by photosynthate partitioning. Therefore, the partitioning of photosynthate to fiber and inner bolls can be used as an important reference for cotton breeding and cultivation.

The phenotypic expression and heritability of quantitative traits vary due to genotypic differences, environmental influences and genotype by environment interactions. The objective of this study was to determine variance components and heritabilities of seed yield and its components in cowpea. Field experiments were conducted at three locations, three planting dates using ten diverse cowpea genotypes during 2004/2005. The experiments were laid out in the randomized complete block design with three replications. Results indicated significant interactions (P ≤ 0.01) among genotypes, locations and planting dates. The genotypic variance contributed ≥50% of the total phenotypic variance for the numbers of days to 50% flowering, seeds per pod, productive branches per plant and seed yield. The heritabilities of the numbers of days to 50% flowering were estimated at 50%, pods per plant (23%), days to maturity (66%), productive branches per plant (53%), 100 seed weight (11%) and seed yield (55%). The presence of considerable degree of genotypic variance among tested genotypes under various environments suggests that success in cowpea breeding could possibly be achieved through direct phenotypic selection.

Effects of growth hormones, rooting media and leaf size on juvenile stem cuttings of Buchholzia coriacea were investigated. Two hundred and sixteen single node cuttings were obtained from two month old seedlings of Buchholzia coriacea. Half had their leaves reduced, while the remaining retained their original leaf size. Cuttings were treated with indole butyric acid (IBA), naphthalene acetic acid (NAA) and a combination of the hormones (IBA/NAA), at 0, 50, 100 and 150 mg/l and planted in three rooting media-topsoil, riversand and sawdust giving a factorial design. Cuttings were assessed for percentage survival, number of roots, length of longest root and total root length. ANOVA was carried out on the data collected and LSD at 5% probability level used to compare significantly different means. Survival percentage of 96.3% was recorded. The highest mean values of 3.8 cm and 12.5 cm in root length and total root length were recorded in topsoil. Control had the highest number of roots - 4.8. Leaf size had a highly significant effect on the rooting of the cuttings as whole leaf rooted better than half leaves. Single node cuttings of Buchholzia coriacea is amenable to cloning with or without auxin treatment.