پديد آورندگان :
عبدلي نسب، مريم دانشگاه تحصيلات تكميلي صنعتي و فناوري پيشرفته كرمان - پژوهشكده علوم محيطي - گروه بيوتكنولوژي , رحيمي، مهدي دانشگاه تحصيلات تكميلي صنعتي و فناوري پيشرفته كرمان - پژوهشكده علوم محيطي - گروه بيوتكنولوژي , رضوان نژاد، الهام دانشگاه تحصيلات تكميلي صنعتي و فناوري پيشرفته كرمان - پژوهشكده علوم محيطي - گروه بيوتكنولوژي
چكيده لاتين :
Introduction Watermelon (Citrullus lanatus) is a tropical or semi-tropical plant and is considered to be a rich source of antioxidant compounds. China is the leading producer of watermelon in the world followed by Turkey, United States, Iran and Republic of Korea. The study of genetic diversity is important not only for the conservation of plant materials, but also for the utilization of the heterosis phenomenon in the breeding programs to produce hybrid seeds with high heterosis in yield, which have greater adaptability and tolerance to biotic and abiotic stress environmental conditions (Abdolinasab & Rahimi, 2017). The province of Kerman is one of the most important regions for watermelon cultivation and production in Iran. In the present study, we used the multivariate statistical analysis based on several morphological and economically important physiological characteristics to evalute the variaton in thirty ecotypes of watermelon that had been collected from differentparts of Kerman province.Material and Methods The collected ecotypes were cultivated in a completely randomized block design with three replications in Kerman. Sixteen morphological and physiological traits were evaluated. Analysis of variance, estimation of the descriptive statistical parameters, cluster analysis, the discriminant and the principal component analysis (PCA), the correlation between traits and the cophenetic correlation coefficient were calculated using different statistical software packages. Components of variance and coefficients of genotypic, phenotypic and environmental variation, also broad sense heritability were calculated with the corresponding formulas. Results & Discussion Analysis of variance revealed significant differences among the investigated traits. Correlation between fruit weight and most of the traits was positive. The length, width and diameter of seeds, which directly affected the seed yield exhibited a positive correlation with this trait. Therefore, they can be viewed as beneficial traits in terms of increasing seed yield. Also, the fruit length, width and diameter as well as flesh weight, which are important yield components in increasing fruit weight, successful variety showed a positive correlation with this trait and can lead to the selection to increase seed and fruit yields. Cluster analysis using ward method classified the studied ecotypes into four groups. Based on the principal component analysis, the first and second components, with characteristic root of higher than 1, justified more than 92 percent of the total variation. The first component represented leaf number trait and the second component represented male flower number trait. NaroeiRad et al., 2010 showed that fruit length, fruit width, fruit weight and yield were the most important traits in the first component and fruit number and seed weight were the most important traits in the second component. Also, Huhl et al., 2008 showed that length, width and weight of fruit were the traits with the greatest importance in the first component. Seed and fruit length traits had the highest heritability (98 %) and the lowest heritability (26 %) was associated with fruit diameter trait. The results of this study showed a great deal of diversity among the morphological traits in the studied ecotypes. The accessions had been divided into four groups in which group 1 produced the highest seed yield. Therefore, the accessions of this group can be used to enhance yield. The Hejrag accession showed the minimum length, width and diameter of seeds, as well as the lowest weight, suggesting that it could be used in the production of small-size seed seed cultivars in breeding programs. Conclusion This study showed that the quantitative traits are a useful tool for preliminary evaluation of genetic diversity in watermelon ecotypes. Based on correlation analysis, the traits including seed diameter, male flower number, number of leaves per plant, number of nodes, fruit length, fruit diameter and fruit weight had positive association with flesh weight. Selection of parent plants should be based on the wider inter-cluster distance and superior mean performance for fruit yield and quality in four distinct groups. The ecotype Yazd was superior for pH, flesh weight and thickness of pericarp, so it can be included in further breeding programs for developing superior varieties. Also, the Neyshabor accession showed the maximum seed length, width, diameter and 100-seed weight, making it suitable for the production of large size seed cultivars.
