Relationship of seed traits on initial progeny growth performance and divergence studies in Madhuca latifolia Macb. for further use in tree improvement

Evaluation of twenty-three genotypes of M. latifolia was carried out based on relationship of seed traits with initial progeny growth performance and divergence studies as a scope for further breeding programme. Variability studies revealed that, more than twelve accessions recorded above average for 100-seed weight (247.5±49.2), oil content (43.8±3.7) and volume index (346.0±97.7). The maximum values observed in studied CPTs were as follows: seed length (39.1 mm) in CPT-15 genotype, seed breadth (19.2 mm) in CPT–8 and CPT–9, aspect ratio (2.2) in CPT-6 and CPT-15, 2D surface area (501.4 and 491.6 mm2) in CPT-9 and CPT-3 respectively. CPT–16 recorded maximum for 100 seed weight (282.4 g) and oil content (51.2%). However, maximum volume index was recorded by CPT–3 (578.3 cm3) followed by CPT–16 (496.0 cm3). The phenotypic and genotypic coefficients of variations are close to each other for all traits, except volume index that exhibited striking difference between PCV (40.0%) and GCV (19.9%) indicating that for most traits genetic control was quite high. Trait oil content and 100 seed weight expressed high heritability (93.5%, 93.0%) accompanied with moderate genetic advance (17.2%, 15.6%), indicating that, heritability is due to additive gene effects and selection may be effective. At genotypic level 100 seed weight registered positive significant correlation with height (0.73) and seed breadth, oil content with volume index (0.55, 0.71). Hence seeds with large breadth, high seed weight and oil content may be selected for producing better progenies. Since traits viz. 100 seed weight and oil content are under strong genetic control, improvement in these characters can bring improvement in volume index. On the basis of the divergence, the 23 genotypes studied were grouped into 5 clusters, indicating wide diversity. The clustering pattern shows that geographical diversity is not necessarily related to genetic diversity. The genotypes in cluster IV and V were most heterogeneous and can be best used for within group hybridization. Cluster means indicated crosses involving under cluster II and V and cluster II and I may result in substantial segregates and further selection for overall improvement of species

Developmenrt of EST-SSR and genomic-SSR markers to assess genetic diversity in Jatropha Curcas L.

<p>Abstract</p> <p>Background</p> <p><it>Jatropha curcas L. </it>has attracted a great deal of attention worldwide, regarding its potential as a new biodiesel crop. However, the understanding of this crop remains very limited and little genomic research has been done. We used simple sequence repeat (SSR) markers that could be transferred from <it>Manihot esculenta </it>(cassava) to analyze the genetic relationships among 45 accessions of <it>J. curcas </it>from our germplasm collection.</p> <p>Results</p> <p>In total, 187 out of 419 expressed sequence tag (EST)-SSR and 54 out of 182 genomic (G)-SSR markers from cassava were polymorphic among the <it>J. curcas </it>accessions. The EST-SSR markers comprised 26.20% dinucleotide repeats, 57.75% trinucleotide repeats, 7.49% tetranucleotide repeats, and 8.56% pentanucleotide repeats, whereas the majority of the G-SSR markers were dinucleotide repeats (62.96%). The 187 EST-SSRs resided in genes that are involved mainly in biological and metabolic processes. Thirty-six EST-SSRs and 20 G-SSRs were chosen to analyze the genetic diversity among 45 <it>J. curcas </it>accessions. A total of 183 polymorphic alleles were detected. On the basis of the distribution of these polymorphic alleles, the 45 accessions were classified into six groups, in which the genotype showed a correlation with geographic origin. The estimated mean genetic diversity index was 0.5572, which suggests that our <it>J. curcas </it>germplasm collection has a high level of genetic diversity. This should facilitate subsequent studies on genetic mapping and molecular breeding.</p> <p>Conclusion</p> <p>We identified 241 novel EST-SSR and G-SSR markers in <it>J. curcas</it>, which should be useful for genetic mapping and quantitative trait loci analysis of important agronomic traits. By using these markers, we found that the intergroup gene diversity of <it>J. curcas </it>was greater than the intragroup diversity, and that the domestication of the species probably occurred partly in America and partly in Hainan, China.</p