Majid Pourrahimi; Seyed Ahmad Sadat-Noori; Fatemeh Amini; Hossein Ramshini
Abstract
We selected ten Ajowan parents (Carum copticum L.) from a genetically diverse population to evaluate gene effects, heritability, and correlations among their morphological traits. We poly-crossed the parents to produce half-sib genotypes. The evaluations comprised the number of days to flowering, plant ...
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We selected ten Ajowan parents (Carum copticum L.) from a genetically diverse population to evaluate gene effects, heritability, and correlations among their morphological traits. We poly-crossed the parents to produce half-sib genotypes. The evaluations comprised the number of days to flowering, plant height, number of fertile branches, number of umbrellas per plant, number of seeds per umbel, seed yield per plant, harvest index, essential oil percentage, and essential oil yield. Parents and polycross progeny seeds grew in a randomized complete block design with three replications at the University of Tehran, 2015-2017. The results showed broad-sense heritability ranged from 0.64 to 0.96 in parents and their progenies. Narrow-sense heritability appeared through the regression of progenies on the parents (h2po) and via progeny analysis (h2n), suggesting that additive genes control these traits. The correlation of seed yield with plant height, number of fertile branches, number of umbrellas per plant, and number of seeds per umbel were positive and significant. The results indicated a significant negative correlation between thymol and γ- terpinene in parents and half-sib families. We reported wide variations and high heritability for most of the evaluated traits in the ajowan populations that can improve seed and essential oil yields.
Karim Arab Salmani; Yousef Hakimi
Abstract
Genetic variability in a crop population is essential for successful plant breeding. Fifteen cucumber genotypes (Cucumis sativus L.) were evaluated in the greenhouse under warm conditions to estimate the magnitude of their genetic variability, trait heritability, morphological features, and pomological ...
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Genetic variability in a crop population is essential for successful plant breeding. Fifteen cucumber genotypes (Cucumis sativus L.) were evaluated in the greenhouse under warm conditions to estimate the magnitude of their genetic variability, trait heritability, morphological features, and pomological characteristics. The genotypes appeared in five categories based on their performance and determination of the most reliable discriminative features that accounted for more significant variability. Cluster Analysis and Principal Component Analysis (PCA) assisted in the classification. The measured characteristics were cucurbit chlorotic yellows virus, fungal severities of infestation, off-type plant, stem, internode, leaf, petiole, fruit and fruit trail length, leaf width, male flower percentage, fruit color and groove, fruit diameter, fruit fresh weight, fruit dry matter and ash percentage, fruit pH, EC and TSS, fruit yield, and total fruit count. The IR4 and IR5 genotypes showed the highest fruit yield (460.85 and 425.86 kg/plot) and number (108.72 and 84.22 fruit/plant). IR11 had the highest value of fruit length (16.60 cm). High broad-sense heritability was associated with all the traits except for cucurbit chlorotic yellows virus and fungal severities of infestation, fruit pH, and total fruit yield. Cluster analysis and its comparison of means showed that IR4 and IR5 from the fifth cluster expressed the best agronomic traits and yield potentials in warm conditions (40 °C/32 °C day/night). Hence, selection for any characteristic would favor genotypes in these clusters. The PCA involved fruit dry matter and TSS as the most discriminating trait that accounted for more significant cucumber variability, which can become crucial information in cucumber improvement programs.
Hossein Astaraki; Hossein Ramshini; Mahmoud Lotfi; Ali Izadi Darbandi
Abstract
Development of cultivars with high yield under normal conditions and maintaining their yield under abiotic stresses is the main purpose of plant breeding programs in arid and semi-arid areas. The present study aimed to evaluate the yield stability of a collection of commercial melon varieties under drought ...
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Development of cultivars with high yield under normal conditions and maintaining their yield under abiotic stresses is the main purpose of plant breeding programs in arid and semi-arid areas. The present study aimed to evaluate the yield stability of a collection of commercial melon varieties under drought stress. The trial was conducted in a field under normal conditions (plants were irrigated after 50 mm evaporation of a class A evaporation pan) and drought stress conditions (irrigation was carried out after 100 mm evaporation of a class A evaporation pan). In average, 3.32 kg fruit/plant and 2.76 kg fruit/plant were obtained under normal and drought stress conditions, respectively. The highest reduction in yield as the consequence of drought exposure was recorded for 'Mazandarani' (52%) and 'Samsoori' (48%). The most drought-tolerant genotypes were 'Mamaghani', 'Nahavandi', 'Shadegan', 'Crenshaw' and 'Suski-e-Sabz' as they had constant yield under both growing conditions. On the other hand, 'Samsoori' and 'Saveh' were the most sensitive genotypes to drought. For most of the measured traits, the values of broad-sense heritability were over 0.50 i.e. there was a large genetic diversity among melon genotypes. This variation can be utilized for selecting high potential fruit yield and drought-tolerant genotypes. Total soluble solids (TSS) (ºBrix) was 15.2% for 'Honey-Dew'. TSS (ºBrix) was obtained 10.7, 10.09, and 9.2% for Iranian genotypes of 'Khatooni', 'Samsoori', and 'Saveh', respectively. In conclusion, although some Iranian melon genotypes were recognized as drought tolerant, they need to be improved for TSS (ºBrix).
Majid Esmaeili; Forouzandeh Soltani; Mohammad Reza Bihamta; Mohammad Javan Nikkhah
Abstract
The purpose of this study was to estimate heritability, general and specific combining ability and the relationship between traits. Investigated traits were fruit number per plant, total yield per plant, average fruit weight, flesh thickness, flesh firmness, seed cavity size, total soluble solid, fruit ...
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The purpose of this study was to estimate heritability, general and specific combining ability and the relationship between traits. Investigated traits were fruit number per plant, total yield per plant, average fruit weight, flesh thickness, flesh firmness, seed cavity size, total soluble solid, fruit length in melon. A complete diallel design was conducted for this purpose five parental genotypes were crossed and the hybrids were evaluated in a randomized complete block design with three replications. Analysis of variance of traits showed a significant differences between hybrids, therefore the first Griffing method was used to analyze the combining ability. The general combining ability effects were significant for all parents in the evaluated traits. The specific combining ability of yield per plant was higher than the general combining ability, which indicates the dominance and non-additive actions of genes. High narrow-sense heritability for yield per plant, flesh firmness and the number of fruit per plant (0.86, 0.72 and 0.70, respectively) indicated low environmental effect for these traits and the greater role of additive effects. The highest narrow-sense heritability was estimated for yield per plant (0.86). The role of non-additive effects of genes in controlling yield and flesh firmness traits was greater than additive effects. Therefore, the preparation of superior hybrids using breeding methods based on progeny tests will be effective in improving the mentioned traits in melon.
