The present study was aimed for identification of the bacterial blight and blast resistant lines in the advanced back cross population of MTU-1010 using marker assisted foreground selection and also for evaluation of agro-morphological characters. The M-16-59 introgressed line (derived from an intercrossing of BC2F1 plants of MTU-1010 x GPP2 and MTU-1010 x NLR 145) is developed under ongoing DBTDBSRR subproject -IV possessing Xa21, xa13, Pi1 and Pi54 resistance genes having broad spectrum resistance to bacterial blight and blast is used as a donor parent and MTU-1010 was used as a recurrent parent for the back cross. Before attempting the backcross both the parents were verified for the target genes along with the original donors GPP2 and NLR 145 using gene specific/linked molecular markers viz., xa13-promo for xa13 gene, pTA248 for Xa21 gene, RM 224 for Pi1 and Pi54 MAS for Pi54. under the F1 generation (equivalent to BC3F1 because two backcrosses were completed earlier), 120 plants were screened, and 16 plants were confirmed for xa13, Xa21, Pi1, and Pi54 genes under heterozygous conditions. These confirmed plants were assessed for agro-morphological characteristics such as yield, grain features, and plant type. The results showed that the confirmed heterozygous plants were comparable to MTU-1010 and passed to the next round of selection and evaluation. The BC1F1-198th plant (96.8%) was selfed to produce BC1F2 population. Twenty five plants were advanced to BC1F3 generation based on BB resistance and above other phenotypic characters. The selected BC1F3 progenies were screened for blast and BB resistance. Four BC1F3 progenies with four target genes (xa13xa13Xa21Xa21Pi54Pi54Pi1Pi1) showed very high level of resistance to both the diseases. BC1F2-198-52nd line found similar to MTU1010 with respect to yield and yield related characters besides showing resistance to both BB and blast.Improved lines of MTU1010 can be advanced for multi-location testing under All India Coordinated Rice Improvement Project (AICRIP) for their evaluation and possible release for the benefit of rice farmers.

BackgroundRice blast and bacterial leaf blight (BLB) are the most limiting factors for rice production in the world which cause yield losses typically ranging from 20 to 30% and can be as high as 50% in some areas of Asia especially India under severe infection conditions.Methods and resultsAn improved line of Tellahamsa, TH-625-491 having two BLB resistance genes (xa13 and Xa21) and two blast resistance genes (Pi54 and Pi1) with 95% Tellahamsa genome was used in the present study. TH-625-491 was validated for all four target genes and was used for backcrossing with Tellahamsa. Seventeen IBC1F1 plants heterozygous for all four target genes, 19 IBC1F2 plants homozygous for four, three and two gene combinations and 19 IBC1F2:3 plants also homozygous for four, three and two gene combinations were observed. Among seventeen IBC1F1 plants, IBC1F1-62 plant recorded highest recurrent parent genome (97.5%) covering 75 polymorphic markers. Out of the total of 920 IBC1F2 plants screened, 19 homozygous plants were homozygous for four, three and two target genes along with bacterial blight resistance. Background analysis was done in all 19 homozygous IBC1F2 plants possessing BLB resistance (possessing xa13, Xa21, Pi54 and Pi1 in different combinations) with five parental polymorphic SSR markers. IBC1F2-62-515 recovered 98.5% recurrent parent genome. The four, three and two gene pyramided lines of Tellahamsa exhibited varying resistance to blast.ConclusionsResults show that there might be presence of antagonistic effect between bacterial blight and blast resistance genes since the lines with Pi54 and Pi1 combination are showing better resistance than the combinations with both bacterial blight and blast resistance genes.

Bacterial blight (BB) and fungal blast diseases are the major biotic constraints that limit rice productivity. To sustain yield improvement in rice, it is necessary to developed yield potential of the rice varieties by incorporation of biotic stress resistance genes. Tellahamsa is a well-adapted popular high yielding rice variety in Telangana state, India. However, the variety is highly susceptible to BB and blast. In this study, simultaneous stepwise transfer of genes through marker-assisted backcross breeding (MABB) strategy was used to introgress two major BB (Xa21 and xa13) and two major blast resistance genes (Pi54 and Pi1) into Tellahamsa. In each generation (from F1 to ICF3) foreground selection was done using gene-specific markers viz., pTA248 (Xa21), xa13prom (xa13), Pi54MAS (Pi54) and RM224 (Pi1). Two independent BC2F1 lines of Tellahamsa/ISM (Cross-I) and Tellahamsa/NLR145 (Cross-II) possessing 92% and 94% recurrent parent genome (RPG) respectively were intercrossed to develop ICF1-ICF3 generations. These gene pyramided lines were evaluated for key agro-morphological traits, quality, and resistance against blast at three different hotspot locations as well as BB at two locations. Two ICF3 gene pyramided lines viz., TH-625-159 and TH-625-491 possessing four genes exhibited a high level of resistance to BB and blast. In the future, these improved Tellahamsa lines could be developed as mega varieties for different agro-climatic zones and also as potential donors for different pre-breeding rice research.

JGL1798 (Jagtial Sannalu) is a high yielding fine grain variety released for Telangana state, India, and highly susceptible to two major rice diseases, bacterial blight (BB) and blast. To improve JGL1798 for BB and blast resistance, two bacterial blight resistance genes (xa13 and Xa21) derived from improved Samba Mahsuri (B95-1) and one blast resistance gene (Pi54) from NLR145 have been introgressed using marker-assisted backcross breeding (MABB) method. Foreground selection was carried out in two independent backcross-derived progenies JGL1798 X B95-1(C5) and JGL1798 X NLR145 (C6) using three gene linked markers viz., xa13 promoter, PTA248, and Pi54MAS. To achieve maximum genome recovery of recurrent parent, background selection was carried out among the gene positive plants at each backcross generation and identified backcross lines having high genome recovery of recurrent parent. Pyramiding three genes into one background, marker-assisted backcrossing was continued until BC2 generation and an intercross was made between highest genome recovery plants, i.e., C5-BC2F1-23and C6-BC2F1-4. The six triple heterozygous positive ICF1 plants confirmed for the presence of xa13, Xa21, and Pi54 genes in heterozygous condition. These plants were screened with polymorphic SSR markers and the ICF124 plant possessing maximum percentage (90%) of recurrent parent genome was selected, selfed and 2216 ICF2 plants were obtained and evaluated during kharif, 2013. A total of 862 plants were genotyped possessing the target resistance genes in homozygous condition. Among those, 11 homozygous plants, the ICF2-4-12 lines possessing the highest genome recovery (92.3%). The identified 11 introgressed lines displayed higher level of resistance to bacterial blight and blast with good agro-morphological traits, grain yield, physical, and cooking quality characters similar to that of JGL1798.

Genetic diversity study was carried out among 41 sesame genotypes using seed yield and its component characters. Based on the present investigation the 41sesame genotypes were grouped into seven clusters suggesting that considerable amount of genetic diversity present across genotypes. The maximum diversity was contributed by capsules per plant followed by number of branches per plant, plant height and days to maturity. Cluster II was the largest one comprising of 17 genotypes followed by cluster I with 12 genotypes, cluster IV with five genotypes, cluster III with four genotypes, cluster V, VI, and VII, were represented by each single genotype indicating high degree of heterogeneity among the genotypes. The maximum inter cluster distance was observed between IV and VI clusters followed by clusters IV and V and clusters VI and VII while it was low between clusters V and VI, followed by clusters I and V, clusters II and VII. Maximum intra cluster distance was observed in cluster VI, followed by cluster IV, cluster III, cluster II and cluster I. The inter cluster distance in most of the cases were higher than the intra-cluster distance indicating wider genetic diversity among the genotypes of different groups. Four characters viz., capsules per plant, followed by number of branches, plant height and days to maturity contributed more than 90% towards genetic divergence. Hence, these four characters are very important for selection indices.

Extent of genetic diversity in a collection of 41 sesame genotypes comprising advanced breeding lines and varieties was assessed based on phenotypic (19 morphological and quantitative traits) and genotypic (68 SSR loci) data. Wide variation was observed for quantitative traits, namely, plant height (86-137 cm). No. of capsules/plant (42-116), days to maturity (81-103) and seed yield/plant (10-23g)., SSR markers showed 29% polymorphism with an average of 2.8 alleles/locus and 0.409 PIC value indicating a trend of moderate level of diversity at molecular level in the collection. The results reinforce the need for using both phenotypic and molecular data for genetic diversity assessments and selecting diverse lines for breeding programmes.

Glutelin protein is the most well-known abundant seed storage protein in rice seed endosperm. A total of 9 glutelin and glutelin type protein sequences from Oryza species available in uniport were evaluated by using bioinformatics tools to investigate physico-chemical properties, secondary structure prediction, putative phosphorylation sites and conserved motif search. Physicochemical analysis offers data such as pI, EC, Al, GRAVY and II about these sequences and the results showed that all glutelin protein sequences are basic, hydrophilic, thermo stable, having some extracellular portion. The secondary structure of the protein sequences were also predicted using SOPMA server. It was observed that alpha helix was predominant, followed by random coil, extended strand and least beta turn was found. Putative phosphorylation sites were also identified which are found to be conserved in plant species and the results showed that the most abundant phosphorylation site is serine residues in glutelin