Informatics Publishing Limited

M. V. Naga Chaithanya ¹, M. R. Dinesh ², C. Vasugi ², D. C. Lakshmana Reddy ¹, D. Sailaja ³, C. Aswath ¹

Affiliations
1 Division of Biotechnology, ICAR- Indian Institute of Horticultural Research, Hesaraghatta Lake Post, Bengaluru-560 089, IN
2 Division of Fruit Crops, ICAR- Indian Institute of Horticultural Research, Hesaraghatta Lake Post, Bengaluru-560 089, IN
3 Department of Biotechnology, Gokaraju Rangaraju Institute of Engineering and Technology, Hyderabad-500090, IN

Abstract

Although the varietal diversity is fairly rich in guava, most varieties lack one or more desirable characters. Hence, attempts were made for improving specific traits, viz., attractive pink pulp colour, soft seeds, medium fruit size, high TSS and high ascorbic acid. Genetic diversity analysis is a prerequisite for identifying potential parents in breeding programs and germplasm conservation. Molecular characterization helps discriminate closely-related genotypes, as, this technique is unaffected by environment, rendering it more reliable. In this study, 48 polymorphic SSRs screened from a total of 115 SSR markers were used for analyzing marker segregation in 72 guava accessions. Statistical analysis was done using IDENTITY1.0 and CERVUS 3.0 software. Cluster analysis was done with DARwin 5.0 software, using Wards Minimum Variance method, and weighted group neighbour joining method, to check reliability of grouping among clusters. The trend in grouping was found to be similar in both methods. Dendrograms generated showed that the hybrids clustered with their parents; exotic collections fell into two different sub-groups based on productivity; the wild species formed one group; and Navalar cultivars from Dharwad clustered together, reflecting similar origin.

Keywords

Guava, Genetic Diversity, Dendrogram, Simple Sequence Repeats.

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K. Khandagale ¹, B. Padmakar ², D. C. Lakshmana Reddy ², Anuradha Sane ³, C. Aswath ²

Affiliations
1 University of Pune, Pune - 411007, IN
2 Division of Biotechnology, ICAR-Indian Institute of Horticultural Research, Hesaraghatta Lake Post, Bengaluru - 560 089, IN
3 Division of Plant Genetic Resources, ICAR-Indian Institute of Horticultural Research, Bengaluru – 5600089, IN

Abstract

Tuberose is one of the most important bulbous ornamentals grown commercially for loose as well as cut flowers. RAPD and ISSR markers used in the study revealed 53% and 73% polymorphism, respectively, among ten tuberose varieties. Polymorphic Information Content (PIC) and Resolving Power (RP) for RAPD varied from 0.35 - 0.46 and 0.8 - 3.6, respectively, and that for ISSR was 0.36 - 0.49 and 0.91 - 4.55, respectively. The dendrogram (UPGMA), based on Jaccards co-efficient as similarity index for RAPD and ISSR, grouped ten varieties into two major clusters, and, combined RAPD-ISSR cluster analysis formed three major clusters based on their genetic relatedness/variation. PCA revealed that the spatial arrangement of these 10 cultivars was congruent with dendrogram analysis. Mantel's test indicated very good correlation, with r = 0.86 for combination of ISSR and RAPD-ISSR. To facilitate identification of tuberose cultivars, a cultivar identification diagram (CID) was developed in which seven ISSR loci could differentiate all the ten cultivars used in the study. Barcodes were developed for five cultivars released by IIHR using 57 polymorphic loci generated by 11 ISSR primers. The size of these loci ranged from 252bp to 2.2kb. These barcodes can be used as a standard reference source for quick identification of cultivars.

Keywords

ISSR, Molecular Barcode, PCR, RAPD, UPGMA.

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Arpita Pattanaik ¹, D. C. Lakshmana Reddy ², S. Ramesh ³, Aswath Chennareddy ⁴

Affiliations
1 Division of Biotechnology, Centre for Post-Graduate Studies, Jain University, Bengaluru 560 011, IN
2 Division of Biotechnology, Indian Institute of Horticultural Research, Hesaraghatta Lake Post, Hesaraghatta, Bengaluru 560 089, IN
3 Department of Genetics and Plant Breeding, College of Agriculture, University of Agricultural Sciences, GKVK, Bengaluru 560 065, IN
4 Division of Floriculture and Medicinal Crops, Indian Institute of Horticultural Research, Bengaluru 560 089, IN

Abstract

Cauliflower (Brassica oleracea) is a cool-season crop belonging to the Brassicaceae family. Use of morphological differences between true-to-types and off-types in grow-out test (GOT) is the basic method for hybrid purity analysis. Traditional GOT is costly, tedious, time consuming and environment sensitive. To increase the speed and accuracy of genetic purity testing of hybrids, recent advances in DNA markers have shown promise. In the present study, the purity of cauliflower hybrid (NBH Tania-815) was assessed by traditional GOT and advanced molecular marker systems. The experiment was carried out by mixing 95% F1 hybrids with 5% female parents, individually in the sample sets of 400, 300, 200, 100, 80 and 40. For each sample size, PCR-based assay and GOT were carried out to check the hybrid purity. In the PCR-based assay, 220 pairs of SSR markers were screened, with 32 markers showing parental polymorphism including one codominant marker (BrgMS565). The purity level was determined by the co-dominant marker. A minimum sample size of 100 was standardized to confirm the hybrid purity as it showed the same result with that of higher sample sizes (200, 300 and 400). Hence, it is proposed that molecular marker-based hybrid purity assessment may serve as an effective substitute to traditional GOT.

Keywords

Cauliflower, Grow-Out Test, Hybrid Purity, PCR Assay.

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Anand C. Reddy ¹, B. Lavanya ¹, T. Tejaswi ¹, E. Sreenivasa Rao ², D. C. Lakshmana Reddy ¹

Affiliations
1 Division of Biotechnology, Indian Institute of Horticultural Research, Bengaluru 560 089, IN
2 Division of Vegetable Crops, Indian Institute of Horticultural Research, Bengaluru 560 089, IN

Abstract

Fusarium wilt (Fusarium oxysporum f. sp. niveum) in watermelon is one of the deadliest diseases around the globe, and availability of disease-resistant varieties is moderate. Disease management utilizing resistance genes (R-genes)/resistance gene analogs (RGAs) has proven to be a promising and successful approach. In the present study, six watermelon RGAs were isolated from wild, fusarium wilt resistant genotype IIHR-82 (Citrullus lanatus var. citroides) using degenerate primers that identify nucleotide binding site-leucine-rich repeat (NBS–LRR) regions. Multiple sequence alignment of these RGAs identified the characteristic NBS– LRR motif, and BLASTp search revealed similarity of these RGAs with other pathogenesis-related proteins. Phylogeny and motif analysis revealed genetic diversity of RGAs within those isolated from watermelon and with other plant R-genes. The watermelon RGAs isolated in this study contained both TIR–NBS–LRR (TNL) and non-TIR–NBS–LRR (CNL) classes of Rgenes. Protein secondary structure prediction of these watermelon RGAs revealed the composition of proteins, including α -helix, β -strand, disordered region and other template-related information. Watermelon RGAs identified in the present study will help in the development of RGA-based markers for resistance to fusarium wilt of watermelon.

Keywords

Disease Management, Fusarium Wilt, Resistance Genes, Watermelon.

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K. K. Jessy Mol ¹, D. C. Lakshmana Reddy ¹, Y. B. Manoj ¹, K. Madhavi Reddy ¹

Affiliations
1 ICAR- Indian Institute of Horticultural Research, Bengaluru-560 089, IN

Abstract

Existence of CGMS system in hot pepper is due to the rearrangements in the mitochondrial genome and is largely used in economized and pure F₁ hybrid seed production around the world. The orf456, a new ORF present at flanking region of the coxII gene at the 3’ end, was distinguished male sterile cytoplasm in hot peppers along with atp6-2gene. In the current study, eighteen pepper genotypes (nine each of A and corresponding B lines) of varied origin were used to validate with two male sterile cytoplasm (S-cytoplasm) specific sequence characterised amplified region (SCAR) markers viz., atp6-2_{(875 bp)} and orf456_{(456 bp)} and one restoration-of-fertility (Rf) locus specific marker, CRF_{(550 bp)}. The results clearly showed that the presence of CMS-S-cytoplasm and absence of restoration-of-fertility (Rf) gene in the pepper genotypes studied and is comparable with the phenotypic data. In view of the outcomes it has been reasoned that the accessible S and Rf markers available in the public domain are reproducible and can be promptly utilized for marker assisted selection (MAS) in hot pepper crop improvement program.

Keywords

CGMS, Hot Pepper, Marker Assisted Selection, Mitochondria, ORF.

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