A comprehensive study was conducted using PPSMV resistant (BSMR 736) and susceptible (ICP 8863) genotypes to develop a segregating population and understand the inheritance of PPSMV resistance. The ...observed segregation was comparable to 13 (susceptible): 3 (resistant). Hence, the inheritance was controlled by two genes, SV1 and SV2, with inhibitory gene interaction.
Root system is a vital part of plants for absorbing soil moisture and nutrients and it influences the drought tolerance. Identification of the genomic regions harbouring quantitative trait loci ...(QTLs) for root and yield traits, and the linked markers can facilitate sorghum improvement through marker-assisted selection (MAS) besides the deeper understanding of the plant response to drought stress. A population of 184 recombinant inbred lines (RILs), derived from E36-1 × SPV570, along with parents were phenotyped for component traits of yield in field and root traits in an above ground rhizotron. High estimates of heritability and genetic advance for all the root traits and for most of the yield traits, presents high scope for improvement of these traits by simple selection. A linkage map constructed with 104 marker loci comprising 50 EST-SSRs, 34 non-genic nuclear SSRs and 20 SNPs, and QTL analysis was performed using composite interval mapping (CIM) approach. A total of eight and 20 QTLs were mapped for root and yield related traits respectively. The QTLs for root volume, root fresh weight and root dry weight were found co-localized on SBI-04, supported by a positive correlation among these traits. Hence, these traits can be improved using the same linked markers. The lack of overlap between the QTLs of component traits of root and yield suggested that these two sets of parameters are independent in their influence and the possibility of combining these two traits might enhance productivity of sorghum under receding moisture condition.
Transcription factors (TFs) are an important target in understanding the regulation of plant responses to environmental stress including moisture stress. Members of the same TF family may differ in ...their response to moisture stress. The expression pattern could vary between shoot and root tissues depending on level of moisture stress. A set of five rarely studied TF families viz., MADS-box (MCM1, AGAMOUS, DEFICIENS and SRF), Auxin Responsive Factor (ARF), Heme Activator Protein 2 (HAP2), Multiprotein Bridging Factor (MBF) and Homeobox (HB) together having 20 members in sorghum, were expression analyzed through quantitative real-time PCR (qRT-PCR) in well watered and moisture stressed shoot and root tissues of sorghum using SYBR Green® to quantify dsDNA synthesis. Fluorescence values were used to calculate PCR efficiency by using LinRegPCR. The PTSb00029.1 and PTSb00033.1 of ARF family and PTSb00174.1 and PTSb00175.1 of HB family recorded 2 to 5, PTSb00221.1 and PTSb00208.1 of MADS family and PTSb00128.1 of HAP2 family recorded 5 to 10 fold up-regulation under moisture stress regimes. The PTSb00128.1, a HAP2 family member, recorded 15 fold up-regulation in mild moisture stressed root tissues. TF genes such as PTSb00218.1, PTSb00220.1, PTSb00031.1, PTSb00032.1, PTSb00034.1 and PTSb00223.1 were found down regulating in both tissues types under moisture stress condition. However, the PTSb00128.1, PTSb00221.1, PTSb00029.1, PTSb00033.1 and PTSb00174.1 TFs were found up-regulating to varied levels in mild and severe moisture stressed root tissues only. Verification of qRT-PCR results was done by in situ hybridization (ISH) of randomly selected two TF genes in shoot and root tissues of sorghum. Taken together, moisture stress triggered up-regulation of more genes in root tissue compared to shoot tissue in sorghum.
Fusarium wilt (Fusarium udum Butler) is a soil borne disease of pigeonpea which causes substantial yield losses. The disease can occur at any stage of plant development, from the young seedling to ...the pod filling stage. Though resistance is simply inherited, transfer to locally adapted cultivars has been difficult due to linkage drag and difficulty in accurate phenotyping, except in sick plots. An attempt was made to identify RAPD markers associated with wilt phenotype by using F2 populations derived from contrasting parents; GSl (susceptible) 'ICPL87119 (resistant) and GS1' ICP8863 (resistant). Parents and F^sub 2^s were grown in a national ^sub Fusarium^ sick-plot at Gulbarga, India and phenotyped as resistant or susceptible during the entire crop growth period. In both the crosses, resistance to wilt segregated as a monogenic dominant character. DNA samples extracted from sick plot grown, early seedling stage plants of parents and 254 F^sub 2^ plants of GS1 × ICPL87119 were held separately for marker identification. PCR reactions using 340 random decamer primers with genomic DNA of parents resulted in detection of 45 polymorphic amplicons from 39 primers. PCR testing of bulked DNA from subsets of resistant and susceptible plants revealed the presence of two amplicons at 704 bp and 500 bp (OPM03704 and OPAC11500) with susceptibility. Analysis of individual F^sub 2^ plants showed a segregation ratio of 3: 1 for the presence: absence of the amplicon in both crosses. Considering the wilt reaction and susceptibility-linked RAPD marker, it was possible to deduce genotype of every F^sub 2^ plant and the genotypic ratio for wilt reaction was 1RR: 2Rr: 1rr, as expected.PUBLICATION ABSTRACT
Stalk rot, also called as charcoal rot in India, caused by Macrophomina phaseolina, is an economically important, soil borne disease in major sorghum growing areas across the world. A population of ...F₉ generation recombinant inbred lines (RILs), derived from IS22380 (susceptible) x E36-1 (resistant), along with parents were phenotyped in sick plots at two locations (Dharwad and Bijapur, Karnataka, India). A total of 85 polymorphic marker loci (62 nuclear and 4 genic SSRs, 19 RAPDs) was available for the construction of genetic map, spanning 650.3 cM in all the ten linkage groups. Analysis with QTL Cartographer (2.5b), adopting composite interval mapping method (LOD > 2.0) at both locations, revealed 5 QTLs at Dharwad and 4 QTLs at Bijapur locations for the component traits of charcoal rot disease resistance. QTLs for number of internodes crossed, length of infection and per cent lodging accounted for 31.83, 10.76 and 18.90 per cent at Dharwad location and 14.87, 10.47 and 26.44 per cent phenotypic variability at Bijapur location, respectively. The QTLs for number of internodes crossed by the rot, length of infection and percent lodging were common across two locations. These QTLs, consistent over environments for the component traits, are likely to assist in marker-assisted selection (MAS) for charcoal rot resistance in sorghum.
The improvement of jackfruit is required to make it amenable for intensive cultivation and make it suitable for a variety of value-added products. There is a significant variation for various traits ...such as plant phenology, leaf shape, leaf size, fruit shape, fruit size, number of fruits per plant, flake colour, number of flakes per fruit etc. The jackfruit crop has long juvenility, high clonal heterozygosity, recalcitrant type of seeds make it difficult to improvement of jackfruit varieties or hybrids, but on the other hand ease of vegetative propagation of hybrids or varieties is advantageous for the jackfruit breeder. The development of jackfruit is again based on the selection of clones especially for small-sized quality fruits, dwarf, less gum type, disease and pest resistance etc. The detailed knowledge on phenology, inheritance pattern and advanced techniques for hybrid/variety development will be useful to overcome the problems of jackfruit breeding viz fruit size, gummier fruits, susceptibility to disease and pests etc. The development of genetic markers has further reduced the uncertainty in the breeding of jackfruit and maintains the hybrid/varietal populations with desirable characteristics.
Pigeonpea Sterility Mosaic Disease (PSMD) is an important foliar disease caused by Pigeonpea sterility mosaic virus (PPSMV) which is transmitted by eriophyid mites (Aceria cajani Channabasavanna). In ...present study, a F2 mapping population comprising 325 individuals was developed by crossing PSMD susceptible genotype (Gullyal white) and PSMD resistant genotype (BSMR 736). We identified a set of 32 out of 300 short decamer random DNA markers that showed polymorphism between Gullyal white and BSMR 736 parents. Among them, eleven DNA markers showed polymorphism including coupling and repulsion phase type of polymorphism across the parents. Bulked Segregant Analysis (BSA), revealed that the DNA marker, IABTPPN7, produced a single coupling phase marker (IABTPPN $7_{414}$) and a repulsion phase marker (IABTPPN $7_{983}$) co-segregating with PSMD reaction. Screening of 325 F2 population using IABTPPN7 revealed that the repulsion phase marker, IABTPPN $7_{983}$, was co-segregating with the PSMD responsive SV1 at a distance of 23.9 cM for Bidar PPSMV isolate. On the other hand, the coupling phase marker IABTPPN $7_{414}$ did not show any linkage with PSMD resistance. Additionally, single marker analysis both IABTPPN $7_{983}$ (P<0.0001) and IABTPPN $7_{414}$ (P<0.0001) recorded a significant association with the PSMD resistance and explained a phenotypic variance of 31 and 36% respectively in $F_2$ population. The repulsion phase marker, IABTPPN7983, could be of use in Marker-Assisted Selection (MAS) in the PPSMV resistance breeding programmes of pigeonpea.
The present investigation was carried out at the farmer’s field Neshwi village, Haveri District of Karnataka, India during kharif season (May, 2021 to January, 2022). The improvement of crop relies ...heavily on genetic diversity. The objective of the study was to assess the genetic divergence of 76 diverse genotypes of ginger collected from different parts of the Karnataka, India which including four checks. The genetic divergence of ginger genotypes was assessed using Mahalanobis D2 statistics. Genetic divergence studies revealed considerable genetic diversity among 76 genotypes of ginger for a set of ten quantitative traits pertaining to the growth and yield characters viz., height of the shoot (cm), leaf area (cm2), number of primary rhizomes, length of the primary rhizome (cm), girth of the primary rhizome (cm), number of secondary rhizomes, length of the secondary rhizome (cm), girth of the secondary rhizome (cm), crop duration (number of days) and rhizome yield plant-1 (g). Analysed 76 ginger genotypes were clustered based on similarities between their D2 values using Tocher’s method, resulting in 14 distinct groups. Considerable diversity within and between 14 clusters was observed among the genotypes. The characteristics such as average rhizome yield plant-1, girth of the primary rhizome and length of the primary rhizome were the main factors in differentiating the genotypes of ginger studied. Utilizing genotypes from clusters with high inter-cluster distances, such as clusters VI and XIII, VI and XIV and X and XIV can form potential pre-breeding material for the improvement of ginger crop.
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