Progress and Prospects of Two Line Rice Breeding in India

Increasing the yield potential through hybrid rice technology was very well proved in nearby countries. Three line hybrid rice technology is encounted with some of the difficulties in seed production. Identification of Environmentally influenced male sterility overcomes the problem encountered in seed production since it is regulated by the temperature it is called temperature regulated male sterility and hybrids produced using this line is called two line rice hybrids. Types of male sterility and methods to identify the new TGMS lines and breeding methods employed for producing the tgms lines were described. Characterization of tgms lines by both conventional method and molecular tools has been enumerated. Seed multiplication of tgms under fertility inducing environment and seed production of two line hybrids has been explained. Seed production location was exclusively identified for seed multiplication of tgms lines. Heterotic potential of two line rice hybrids has been studied. Future prospectes in tgms research and two line heterotic potential was explained for increasing the yield potential in rice

Genetic Potential and Possible Improvement of <em>Sesamum indicum</em> L.

Sesame (Sesamum indicum L.) is one of the traditional oil seed crop widely cultivated in many countries. The top producers of sesame seeds are mainly Tanzania, Myanmar, India, China and Japan. Sesame oil contains high level of unsaturated fatty acids (80%) and low levels of saturated fatty acids (20%). The main fatty acids are palmitic, stearic, oleic, linoleic and trace amounts of linolenic fatty acids. Sesame seed contains 50–60% of high-quality oil rich in natural antioxidants such as sesamin, sesamolin, sesaminol and sesamol it enhances the stability and keeping quality of sesame oil. Sesame seeds have good sources of dietary fibre, fats, vitamins, minerals, proteins and rich in anti-oxidants. Polyunsaturated fatty acids in sesame will reduce the risk of high blood pressure, cardiac disorders and blood sugar levels. Sesame is believed to have been originated in India where maximum variability of genetic resources is available. High yielding varieties available to date have reached the yield plateau even with the advanced cultivation practices. The area under oilseed crops cultivation also reducing every year. Hence, there is an urgent need to increase the oil content and yield of Indian sesame varieties. Understanding the available germplasm and novel interventions to develop high yielding varieties warrant both molecular and phenotypic data which is meagre in case of sesame

Character association and path analysis in bacterial blight resistance genes pyramided segregating populations of rice (Oryza sativa L.)

An exploratory research work was conducted to study the character association and their direct and indirect effects on grain yield in three bacterial blight resistance genes introgressed segregating populations (F2) in rice. Data for yield and five other traits which were component of yield were recorded in 449 F2 individuals in all three crosses. Thousand grain weight was highly correlated with single plant yield in (r=0.95**, p<0.01) CB 174 R × IRBB 60> (r=0.48**, p (r=0.44**, p<0.01) TNAU CMS 2B × IRBB 60. Thousand grain weight was exhibited important yield determining component for CB 174 R × IRBB 60 (0.92) and CB 87 R × IRBB 60 (0.45), and panicle length for (0.39) TNAU CMS 2B × IRBB 60 by direct effect. The genetic information derived from our study could be useful to select potential segregating individual among the F2 population for future rice breeding program

Variability and genetic diversity study in an advanced segregating population of rice with bacterial blight resistance genes introgressed

ABSTRACT Bacterial blight disease of rice caused by Xanthomonas oryzae pv. oryzae is one of the most important widespread disease around the globe and can cause severe yield reductions of up to 30% of the total yield. Genetic variability was studied in 54 families of CB 174 R × IRBB 60 rice with bacterial blight resistance genes introgressed at the Department of Rice, Tamil Nadu Agricultural University, Coimbatore, India. Traits such as plant height and the number of productive tillers per plant were found to have negative skewness in this study, indicating the duplication of gene effects. Panicle length and the number of grains per panicle were found to have positive kurtosis, indicating gene interactions. The phenotypic coefficient of variation was slightly higher than the genotypic coefficient of variation for all traits, indicating that the observed variation was not only due to genotypic but also due to the environmental effect on the expression of these traits. High heritability coupled with high genetic advance as a percent of the mean was observed for plant height. Moreover, moderate heritability coupled with high genetic advance as a percent of the mean was observed for the single plant yield of rice. Cluster and principal component analyses revealed that the 54 F2:3 families were grouped into three clusters based on six agro-morphological traits. Clusters III and II had higher mean values for most of the studied traits than cluster I. Intercrossing lines from distinct clusters can be identified and crossed to generate larger variability to produce desirable recombinants for higher yield with a wide genetic base

Effectiveness of selection, parent-offspring correlation and regression in bacterial blight resistance genes introgressed rice segregating population

ABSTRACT: The effectiveness of early generation selection was practiced in bacterial blight resistance genes introgressed F2 and F2:3 population of the cross CB 174 R × IRBB 60 in rice. F2 Selection have been proved to be robust and effective tool in crop improvement program. Selection differential was positive for all studied traits. Selection response was high for number of grains, thus indicating the effectiveness of selection for these character. Realized heritability was found high for number of grains and thousand grain weight, suggested that direct selection was effective. Expected selection response and predicted genetic gain was high for number of grains. Parent-offspring correlation showed low but significance association for number of productive tillers (r=0.47**, P<0.01), single plant yield (r=0.35**, P<0.01) and (r=0.30*, P<0.05) panicle length in F2 and F2:3 generation indicates that selection was fruitful in early generation. Statistically regression coefficient was not significant linear dependence of the mean of F2 and F2:3 generation

Assessing the Genetic Diversity of Parents for Developing Hybrids Through Morphological and Molecular Markers in Rice (Oryza sativa L.)

Abstract The advancement of hybrid technology plays a crucial role in addressing yield plateau and diminishing resources in rice cultivating regions. The knowledge of genetic diversity among parental lines is a prerequisite for effective hybrid breeding program. In the current study, a set of 66 parental lines was studied for diversity based on both morphological characters and microsatellite SSR markers. The genetic variability parameters unveiled that number of productive tillers per plant, single plant yield and hundred grain weight exhibited additive gene action. Mahalanobis D2 statistics grouped the genotypes into ten clusters based on yield and grain traits. The principal component analysis identified four PCs with eigen value more than one accounting for 71.28% of cumulative variance. The polymorphic SSR markers produced 122 alleles among which the marker RM474 recorded the highest values for Polymorphic Information Content (0.83) and heterozygosity index (0.85). The genotypes were assembled in seven clusters based on jaccard distances using the Unweighted Pair Group method with Arithmetic Mean (UPGMA). The population structure divided the entire population into 3 subpopulations. In both clustering, there was difference in the assembling of genotypes, but, good performing genotypes identified through PCA were positioned in different clusters in both approaches. The genotypes CBSN 495 and CBSN 494 located in different clusters were identified as the potential restorers for high yielding and short duration hybrids. The hybridization among CRR Dhan 310, CRR Dhan 315, IR64 DRT, CB 17135 and WGL 347 can be performed to develop climate smart varieties with improved nutrition

Genetic Improvement of Drought Tolerance in a Mega-Rice Variety Improved White Ponni through Marker-Assisted Backcross Breeding

In the ever-changing climatic conditions, it has become important to enhance rice productivity to ensure global food security. Drought is one of the major limiting factors in rice pro- duction. Drought during the reproductive stage results in maximum or complete yield loss. Efforts have been taken to develop drought-tolerant rice lines by introgressing three major drought-effect QTLs, viz. qDTY1.1, qDTY2.1, and qDTY3.1, from Apo into a susceptible popular rice variety, Improved White Ponni (IWP). Backcross inbred lines of IWP × Apo were developed through the marker-assisted backcross breeding approach. Foreground analysis using linked markers resulted in the identification of 17 progenies carrying two or more QTLs, and the recurrent parent genome recoveries of these lines were >95.6% using 72 genome-wide SSR markers distributed throughout all chromosomes. Upon phenotypic evaluation of 17 IWP BILs, the water limited condition resulted in the identification of improved lines by recording the yield and the yield-related parameters. The promising performance of IWP BILs in terms of spikelet fertility (63.3%) and grain yield per plant (>10 g) under drought stress indicated the positive effects of introgressed qDTYs, while IWP recorded complete yield loss (94.2%). Out of the cultivars considered, the best-performing lines which truly exhibited drought tolerance, with more increased yield than the recurrent parent under water-limited conditions, and the effects of these QTLs and their interactions were examined in this research work

Calcium-Rich Pigeonpea Seed Coat: A Potential Byproduct for Food and Pharmaceutical Industries

Pigeonpea is a protein-rich legume which is consumed worldwide in a variety of forms (whole seed, dhal, and as a green vegetable). In India, pigeonpea is milled to yield dhal (cotyledon) and this process generates 25–35% waste byproducts. The hull (seed coat) which accounts for 10% of the byproduct is disposed of either as waste or low-cost cattle feed. To recycle the waste byproducts into the food value chain, this study was conducted with the objectives: (i) to estimate nutrient accumulation in the major seed fractions (cotyledon and seed coat), (ii) to estimate the percentage of nutrient contribution by major seed fractions, (iii) to assess the percentage of nutrient loss due to dehulling, and (iv) to determine the scope of seed coat in nutritional value addition. For this, a subset of 60 diverse pigeonpea accessions selected from 600 pigeonpea accessions raised during the 2019 and 2020 rainy seasons at ICRISAT, Patancheru, India, was subjected to a cotyledon and seed coat nutrient analysis. The three-way analysis of variance revealed the significant influence of cropping years, seed fractions, genotypes, and their interactions on nutrient accumulation. The nutrients, namely protein (32.28 ± 2.29%), P (476.51 ± 39.05 mg/100 g), K (1557.73 ± 66.82 mg/100 g), Fe (4.42 ± 0.41 mg/100 g), Zn (2.25 ± 0.21 mg/100 g), and Cu (0.95 ± 0.07 mg/100 g) were enriched in cotyledon. Mn was equally enriched in both the cotyledon and seed coat (1.02 ± 0.12 mg/100 g and 0.97 ± 0.34 mg/100 g, respectively). The seed coat had a high concentration of Ca (652.02 ± 114.82 mg/100 g), and Mg (249.19 ± 34.12 mg/100 g) with wide variability for Fe (2.74–5.61 mg/100 g), Zn (0.88–3.95 mg/100 g), Cu (0.38–1.44 mg/100 g), and Mn (0.58–2.18 mg/100 g). It is noteworthy that the protein and P contents in the cotyledon were 7 and 18 times higher than that in the seed coat, respectively, and the Ca content in the seed coat was 12 times higher than that in the cotyledon. A correlation study revealed that for overall nutrient improvement in dhal, selection for a small seed size was desirable. On an average, the percentage of nutrient contribution by major seed fractions revealed that the cotyledon portion contributed around 95% protein and P; 90% K and Zn; 85% Fe, Cu, and Mn; and 75% Mg, while the seed coat portion contributed nearly 65% Ca to the whole grain. The findings of high Fe and protein concentrations in the cotyledon and high Ca accumulation in the seed coat can serve as a new guide for improved technological fractionation of these components to serve as a novel functional food ingredient and as a dietary supplement that can address malnutrition

Additional file 3: Table S2. of Analysis of Population Structure and Genetic Diversity in Rice Germplasm Using SSR Markers: An Initiative Towards Association Mapping of Agronomic Traits in Oryza Sativa

Allele matrix of 192 accessions x 61 SSRs. (XLSX 10 kb