Development of Elongated Uppermost Internode CMS Lines for Hybrid Rice Breeding in India

Development of cytoplasmic male sterile (CMS) lines with elongated uppermost intemode (EUI) trait provides a genetic option to eliminate the use of GA3 in hybrid rice.     

Analysis of mortality pattern among indigenous and upgraded pigs under subtropical hill agro climatic conditions in eastern Himalayas

Mortality records of indigenous and upgraded pigs, reared under subtropical hill agro climatic conditions, were collected for the period of 11 years (1993–2003), analyzed and the mortality pattern was correlated with genetic group, age of pigs, climatic factors and causes of death. Results revealed that there was significant (p < 0.05) difference in mortality between the indigenous (6.05%) and upgraded (5.64%) pigs. The mortality percentage was significantly (p < 0.05) higher in both genetic groups between 0 and 4 months of age compared to seven months and above age groups. Among different seasons, significantly (p < 0.05) higher mortality was observed during post-monsoon and winter compared to other seasons. The overall mortality percentage was 4.74, 5.25, 7.51 and 6.56 during pre-monsoon, monsoon, post-monsoon and winter seasons, respectively. Indigenous pigs recorded significantly (p < 0.05) higher pre-weaning mortality (14.26%) than the upgraded (9.58%) pigs. Among different causes, digestive disorders accounted to significantly (p < 0.05) higher mortality followed by miscellaneous and respiratory disorders. The study developed a linear regression model, which could fairly predict the mortality pattern based on the rainfall, relative humidity and temperature (R² = 58.3%).     

Effect of probiotic supplementation on growth,nitrogen utilisation and serum cholesterol in broilers

1. The effect of dietary probiotic supplementation on the growth, nitrogen utilisation and serum cholesterol content of broiler chickens was studied in 2 trials.

2. In experiment 1, the birds receiving the 0, 75, 100, 125 mg probiotic/kg diets had weight gains of 1204.0, 1272.0, 1268.3 and 1210.5 g, respectively at the end of 8 weeks of feeding. The group of birds fed on the 75 mg probiotic supplemented diet retained significantly (P<0.01) more nitrogen than the control birds. Serum cholesterol content was lower in the probiotic‐supplemented birds (93.3 mg/100 ml) compared to the control birds (132.2 mg/100 ml).

3. In the second experiment the probiotic plus antibiotic‐supplemented group of birds had the maximum weight gain (1148.5 g) followed by antibiotic (1141.3 g), probiotic‐supplemented (1128.4 g) and control birds (1045.6 g) after 6 weeks. Nitrogen retention was greatest in the antibiotic—(48.5%) followed by the probiotic—(46.5%), probiotic plus antibiotic‐supplemented groups (46.3%) compared to 40.2% in control birds.

4. The apparent metabolisable energy was greatest in birds receiving the probiotic plus antibiotic‐supplemented diet (12.37 MJ/kg) followed by antibiotic—(12.00 MJ/kg), probiotic‐supplemented birds (11.92 MJ/kg) than in control birds (11.62 MJ/kg). Serum cholesterol was significantly (P<0.01) lower in probiotic‐supplemented birds (86.1 mg/dl) compared to 118.4 mg/dl in control birds.     

Development of tomato SSR markers from anchored BAC clones of chromosome 12 and their application for genetic diversity analysis and linkage mapping

In this study, we developed a total of 37 simple sequence repeat (SSR) markers from 11 bacterial artificial chromosome (BAC) clone sequences anchored on chromosome 12 of tomato available at Solanaceae Genomics Network. These SSR markers could group a set of 16 tomato genotypes comprising of Solanum lycopersicum, S. pimpinellifolium, S. habrochaites, and S. pennellii unambiguously according to their known species status. Clear subgroups of genotypes within S. lycopersicum were also observed. A subset of 16 SSR markers representing the 11 BAC clones was used for developing genetic linkage maps of three interspecific F₂ populations produced from the crosses involving a common S. lycopersicum parent (CLN2498E) with S. pennellii (LA1940), S. habrochaites (LA407) and S. pimpinellifolium (LA1579). The length of the genetic linkage maps were 112.5 cM, 109.3 cM and 114.1 cM, respectively. Finally, an integrated genetic linkage map spanning a total length of 118.7 cM was developed. The reported SSR markers are uniformly distributed on chromosome 12 and would be useful for genetic diversity and mapping studies in tomato.     

Detection of quantitative trait loci (QTL) associated with resistance to whitebacked planthopper (Sogatella furcifera) in rice (Oryza sativa)

Whitebacked planthopper (WBPH) is an important insect pest of rice. In this study, we report quantitative trait loci (QTL) associated with resistance to WBPH using a doubled‐haploid (DH) mapping population derived from the cross IR64/Azucena. We evaluated a set of 91 DH lines using various screening tests which measure seedling resistance, antibiosis and tolerance to WBPH. QTL analysis involving a RFLP map of 175 markers detected a significant QTL on chromosome 7 (RG511‐RG477) associated with seedling resistance to WBPH. In addition, QTL analysis involving available defence related candidate genes as markers on a sub set of 60 DH lines showed significant association of genomic regions on chromosome 1 (W1‐pMRF1), 2 (XLRfrI7‐RG157) and 7 (RG711‐CDO418) with resistance to WBPH. Several suggestive QTL were detected on chromosomes 2, 3, 6, 7, 8 and 11 showing the possibility of their association with resistance to WBPH. The phenotypic contribution of the QTL ranged from 8.4% to 32.1%. Some of the WBPH resistance QTL detected in this study showed similar map positions with the QTL reported for resistance to brown planthopper (BPH) in the same mapping population. These results would be useful for attempts to trace the genes associated with resistance to planthoppers in rice.