RESUMEN
Citrullus colocynthis (L.) Schrad. (Cucurbitaceae) shows high levels of variation in fruit color, fruit stripe pattern, seed coat color, and size. Thirty-eight accessions of C. colocynthis plants from different parts of semi-arid Rajasthan were collected and genetic diversity was assessed using random-amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) markers. Out of 65 RAPD decamer primers, 50 primers produced 549 scorable bands of which 318 were polymorphic. Polymorphic banding patterns with the number of amplified fragments varied from 5 (OPA-08 and OPF-9) to 19 (OPT-20) in the molecular size range of 150-6000 bp. Percent polymorphism ranged from 22.2% (OPA-09) to 83.3% (OPE-12) with 55.14% polymorphism. Out of the 20 ISSR primers screened, 13 primers produced 166 amplification products, of which 99 were polymorphic. The number of bands amplified per primer varied between 9 (UBC-807, 802) and 16 (UBC-803, 812) with average band size between 250 and 4000 bp. Percent polymorphism ranged from 45.4% (UBC-815) to 73.3% (UBC-814) with 65.05% polymorphism. Dendrogram constructed on the basis of RAPD + ISSR polymorphism separated the accessions into four distinct clusters at 72% variation with Jaccard's similarity coefficient ranging from minimum 0.64 to 0.95. The matrices for RAPD and ISSR were also compared using Mantel's test and obtained correlation value (r = 0.7947). Discriminating power of RAPD and ISSR markers was assessed by calculating polymorphic information content, multiplex ratio, marker index, and resolving power. Approx. 50% RAPD and ISSR markers showed PIC value and heterozygosity (H) ≥ 0.50, indicating marker as informative. The primers that showed higher polymorphism had higher RP, MR, and MI values.
RESUMEN
Expressed sequence tags (ESTs) are important resource for gene discovery, gene expression and its regulation, molecular marker development, and comparative genomics. We procured 10000 ESTs and analyzed 267 EST-SSRs markers through computational approach. The average density was one SSR/10.45 kb or 6.4% frequency, wherein trinucleotide repeats (66.74%) were the most abundant followed by di- (26.10%), tetra- (4.67%), penta- (1.5%), and hexanucleotide (1.2%) repeats. Functional annotations were done and after-effect newly developed 63 EST-SSRs were used for cross transferability, genetic diversity, and bulk segregation analysis (BSA). Out of 63 EST-SSRs, 42 markers were identified owing to their expansion genetics across 20 different plants which amplified 519 alleles at 180 loci with an average of 2.88 alleles/locus and the polymorphic information content (PIC) ranged from 0.51 to 0.93 with an average of 0.83. The cross transferability ranged from 25% for wheat to 97.22% for Schlerostachya, with an average of 55.86%, and genetic relationships were established based on diversification among them. Moreover, 10 EST-SSRs were recognized as important markers between bulks of pooled DNA of sugarcane cultivars through BSA. This study highlights the employability of the markers in transferability, genetic diversity in grass species, and distinguished sugarcane bulks.
