RESUMEN
Understanding the genetic diversity of different Pakistani mango varieties is important for germplasm management and varietal characterization. Microsatellites are efficient and highly polymorphic markers for comparative genome mapping, and were used in the present study to determine the genetic relatedness and variability among 15 indigenous mango cultivars (Mangifera indica L.). Overall, 181 bands were produced using 12 simple sequence repeat (SSR) primers. Out of the 12 primers used, 10 were polymorphic and two were monomorphic. Genetic relatedness among cultivars was assessed by constructing a dendrogram using the unweighted pair group method of arithmetic means. The accessions exhibited coefficients of similarity ranging from 75 to 100%, indicating the frequent use of only a few parent cultivars and the presence of inbreeding. The primers used in the present study were found to be valuable for identifying genetic relationships among mango cultivars.
Asunto(s)
Mangifera/genética , Cartilla de ADN , ADN de Plantas/genética , Marcadores Genéticos , Variación Genética , Repeticiones de Microsatélite , Pakistán , Filogenia , Fitomejoramiento , Hojas de la Planta/genética , Polimorfismo GenéticoRESUMEN
In Pakistan, cotton crop has been under enormous threat of cotton leaf curl disease (CLCuD) over the last four decades. In order to estimate genetic diversity in cotton germplasm CLCuD resistance, we assessed 100 cotton genotypes for their CLCuD resistance/tolerance and other related agronomical traits. Various statistical analytical tools, including correlation analysis, cluster analysis, and principal component analysis (PCA), were used to select the best genotypes. These genotypes can be used in future breeding programs to generate CLCuD resistant varieties. The same set of procedures could be utilized for other diseases in other crops. CLCuD incidence showed a significant negative genotypic correlation with yield-contributing traits followed by a significant negative association for phenotypic correlation. The seed cotton yield showed significant positive genotypic and phenotypic correlations with plant height, number of bolls per plant, and boll weight. From the PCA we identified five principal components (PCs) that explained a significant amount of the variance among the variables, which may be used for selection of cotton genotypes with CLCuD resistance. Of the five PCs, the first four contributed more towards the total variability and had eigenvalues greater than one. The cluster analysis showed that the genotypes in one of the clusters performed particularly well with respect to CLCuD tolerance. These genotypes can be utilized for development of varieties with increased CLCuD tolerance.
Asunto(s)
Resistencia a la Enfermedad/genética , Variación Genética , Genotipo , Gossypium/genética , Enfermedades de las Plantas/genética , Carácter Cuantitativo Heredable , Análisis por Conglomerados , FenotipoRESUMEN
This study aimed to identify high-yielding peanut genotypes with resistance to leaf spot disease. The experiments included material from fourteen local and four exotic peanut genotypes that showed highly significant differences among morphological and disease severity parameters in all the genotypes which, in turn, suggested diversity genotypes. Disease severity analysis showed that the highest disease score and damaged leaf area were observed in the genotype Kelincer and the lowest scores and leaf damaged areas were observed in Majalaya super and BARI-2000, respectively. Based on these results, the genotypes BARI-2011, Chakori, Golden, BARI-89, Majalaya Super, BARD-699, BARI-2000, SP-1, and No. 334 can be used by breeders in peanut improvement programs for the development of new cultivars with higher disease resistance and increased yield.
Asunto(s)
Arachis/genética , Resistencia a la Enfermedad/genética , Enfermedades de las Plantas/genética , Hojas de la Planta/genética , Semillas/genética , Arachis/crecimiento & desarrollo , Arachis/microbiología , Genes de Plantas , Estudios de Asociación Genética , Predisposición Genética a la Enfermedad , Genotipo , Enfermedades de las Plantas/microbiología , Hojas de la Planta/crecimiento & desarrollo , Hojas de la Planta/microbiología , Semillas/crecimiento & desarrollo , Semillas/microbiologíaRESUMEN
Interspecific and intraspecific hybrids show varying degrees of heterosis for yield and yield components. Yield-component traits have complex genetic relationships with each other. To determine the relationship of yield-component traits and fiber traits with seed cotton yield, six lines (Bt. CIM-599, CIM-573, MNH-786, CIM-554, BH-167, and GIZA-7) and three test lines (MNH-886, V4, and CIM-557) were crossed in a line x tester mating design. Heterosis was observed for seed cotton yield, fiber traits, and for other yield-component traits. Heterosis in interspecific hybrids for seed cotton yield was more prominent than in intraspecific hybrids. The interspecific hybrid Giza-7 x MNH-886 had the highest heterosis (114.77), while among intraspecific hybrids, CIM-554 x CIM-557 had the highest heterosis (61.29) for seed cotton yield. A major trait contributing to seed cotton yield was bolls/plant followed by boll weight. Correlation studies revealed that bolls/plant, boll weight, lint weight/boll, lint index, seed index, lint/seed, staple length, and staple strength were significantly and positively associated with seed cotton yield. Selection based on boll weight, boll number, lint weight/boll, and lint index will be helpful for improving cotton seed yield.
Asunto(s)
Gossypium/genética , Vigor Híbrido , Hibridación Genética , Fibra de Algodón/normas , Endogamia , Fitomejoramiento , Carácter Cuantitativo Heredable , Selección ArtificialRESUMEN
We conducted a 5 x 5 complete diallel cross experiment in bread wheat (Triticum aestivum) with the genotypes 6309, Chkwal-50, Dhrabi, Bhkhar-02, and FS-08. Our objective was to evaluate the type of gene action and the general and specific combining abilities required for various morphological traits in wheat. The results of analysis of variance revealed highly significant differences among genotypes for all the investigated traits. The results of joint regression analysis showed that the data for all the investigated traits fitted a simple additive dominance model. Graphical representation of variance and covariance suggested that most of the investigated traits were controlled by overdominance gene action. However, the peduncle length and plant height were controlled by additive gene action. Variety 6309 carried the highest number of dominant genes for the number of spikelets per spike, number of tillers per plant, plant height, number of fertile tillers per plant, and grain yield per plant. Chakwal-50 carried the highest number of recessive genes for grain yield per plant, number of tillers per plant, number of grains per spike, number of fertile tillers per plant, and plant height. Chakwal-50 and 6309 were the best general combiners for number of spikelets per spike, number of grains per spike, grain yield per plant, 1000-grain weight, number of fertile tillers per plant, and number of tillers per plant. On other hand, 6309 performed well in specific crosses with Chakwal-50, FS-08, and Bhakhar-02 for spike length and number of tillers per plant.
Asunto(s)
Triticum/crecimiento & desarrollo , Triticum/genética , Cruzamientos Genéticos , Genotipo , Triticum/fisiologíaRESUMEN
Biofuel tree species are recognized as a promising alternative source of fuel to conventional forms. Additionally, these tree species are also effective in accumulating toxic heavy metals present in some industrial effluents. In developing countries such as Pakistan, the use of biofuel tree species is gaining popularity not only for harvesting economical and environmentally friendly biofuel, but also to sequester poisonous heavy metals from industrial wastewater. This study was aimed at evaluating the genetic potential of two biofuel species, namely, Jatropha curcas and Pongamia pinnata, to grow when irrigated with industrial effluent from the Pak-Arab Fertilizer Factory Multan, Southern Punjab, Pakistan. The growth performances of one-year-old seedlings of both species were compared in soil with adverse physiochemical properties. It was found that J. curcas was better able to withstand the toxicity of the heavy metals present in the fertilizer factory effluent. J. curcas showed maximum gain in height, diameter, and biomass production in soil irrigated with 75% concentrated industrial effluent. In contrast, P. pinnata showed a significant reduction in growth in soil irrigated with more than 50% concentrated industrial effluent, indicating that this species is less tolerant to higher toxicity levels of industrial effluent. This study identifies J. curcas as a promising biofuel tree species that can be grown using industrial wastewater.