Genetic gain for rice yield in rainfed environments in India.

The complexity of genotype × environment interactions under drought reduces heritability, which determines the effectiveness of selection for drought tolerance and development of drought tolerant varieties. Genetic progress measured through changes in yield performance over time is important in determining the efficiency of breeding programmes in which test cultivars are replaced each year on the assumption that the new cultivars will surpass the older cultivars. The goal of our study was to determine the annual rate of genetic gain for rice grain yield in a drought-prone rainfed system in a series of multi-environment trials conducted from 2005 to 2014 under the Drought Breeding Network of Indian sites in collaboration with the International Rice Research Institute (IRRI). Our results show a positive trend in grain yield with an annual genetic yield increase of about 0.68 % under irrigated control, 0.87 % under moderate reproductive stage drought stress and 1.9 % under severe reproductive stage drought stress due to breeding efforts. The study also demonstrates the effectiveness of direct selection for grain yield under both irrigated control as well as managed drought stress screening to improve yield in typical rainfed systems. IRRI's drought breeding programme has exhibited a significant positive trend in genetic gain for grain yield over the years under both drought stress as well as favorable irrigated control conditions. Several drought tolerant varieties released from the programme have outperformed the currently grown varieties under varied conditions in the rainfed environments on farmers' fields.

Gender focused training and knowledge enhances the adoption of climate resilient seeds.

Adoption of any agricultural technology depends upon the way in which farmers are being informed about its benefits. Educational status, caste, gender and other social issues also play a significant role in the adoption process. To evaluate the impact of trainings on quality seed production, access to the climate resilient rice seeds, availability of information about seed sources and use of IRRI super bags, a randomized experimental research was carried out over a period of two years across five different states of India. The baseline and a follow-up survey was conducted to capture the farming practices followed by during wet seasons of 2016 and 2017, respectively. The impact of trainings, seed use, information given and agro-based goods was evaluated by comparing the adoption behaviour of treatment and control farmers. There was an increase (28.8%) in the practice of using salt solution to clean seeds primarily due to the impact of quality seed production (QSP) trainings. Female farmers responded more than the male farmers as number of women adopting the practice was higher than men. The impact of the trainings on farmers' knowledge and adoption of climate resilient/stress tolerant rice varieties (STRV) was also more pronounced on females than on male farmers. Farmers' access to seeds substantially enhanced the adoption and reusability irrespective of the gender. Similarly, the information delivered to the farmers was quite economical in enhancing the awareness and adoption of climate resilient rice, but the effect was predominantly driven by female farmers. Female farmers performed relatively better with respect to the storing the new seeds in IRRI super bags. Thus, incentivising farmers in general and female farmers in particular can serve as a potential means to adopt agricultural technologies that have potential to boost rural economy and enhance the food security. The results are being supported by a rigorous empirical analysis.

No yield penalty under favorable conditions paving the way for successful adoption of flood tolerant rice.

Flooding is one of the major constraints for rice production in rainfed lowlands, especially in years and areas of high rainfall. Incorporating the Sub1 (Submergence1) gene into high yielding popular varieties has proven to be the most feasible approach to sustain rice production in submergence-prone areas. Introgression of this QTL into popular varieties has resulted in considerable improvement in yield after flooding. However, its impact under non-flooded conditions or years have not been thoroughly evaluated which is important for the farmers to accept and adopt any new version of their popular varieties. The present study was carried out to evaluate the effect of Sub1 on grain yield of rice in different genetic backgrounds, under non-submergence conditions, over years and locations. The study was carried out using head to head trials in farmer's fields, which enable the farmers to more accurately compare the performance of Sub1 varieties with their recurrent parents under own management. The data generated from different head to head trials revealed that the grain yield of Sub1 varieties was either statistically similar or higher than their non-Sub1 counterparts under non-submergence conditions. Thus, Sub1 rice varieties show no instance of yield penalty of the introgressed gene.

Heterosis and correlation in interspecific and intraspecific hybrids of cotton.

Interspecific and intraspecific hybrids show varying degrees of heterosis for yield and yield components. Yield-component traits have complex genetic relationships with each other. To determine the relationship of yield-component traits and fiber traits with seed cotton yield, six lines (Bt. CIM-599, CIM-573, MNH-786, CIM-554, BH-167, and GIZA-7) and three test lines (MNH-886, V4, and CIM-557) were crossed in a line x tester mating design. Heterosis was observed for seed cotton yield, fiber traits, and for other yield-component traits. Heterosis in interspecific hybrids for seed cotton yield was more prominent than in intraspecific hybrids. The interspecific hybrid Giza-7 x MNH-886 had the highest heterosis (114.77), while among intraspecific hybrids, CIM-554 x CIM-557 had the highest heterosis (61.29) for seed cotton yield. A major trait contributing to seed cotton yield was bolls/plant followed by boll weight. Correlation studies revealed that bolls/plant, boll weight, lint weight/boll, lint index, seed index, lint/seed, staple length, and staple strength were significantly and positively associated with seed cotton yield. Selection based on boll weight, boll number, lint weight/boll, and lint index will be helpful for improving cotton seed yield.

Flood-tolerant rice reduces yield variability and raises expected yield, differentially benefitting socially disadvantaged groups.

Approximately 30% of the cultivated rice area in India is prone to crop damage from prolonged flooding. We use a randomized field experiment in 128 villages of Orissa India to show that Swarna-Sub1, a recently released submergence-tolerant rice variety, has significant positive impacts on rice yield when fields are submerged for 7 to 14 days with no yield penalty without flooding. We estimate that Swarna-Sub1 offers an approximate 45% increase in yields over the current popular variety when fields are submerged for 10 days. We show additionally that low-lying areas prone to flooding tend to be more heavily occupied by people belonging to lower caste social groups. Thus, a policy relevant implication of our findings is that flood-tolerant rice can deliver both efficiency gains, through reduced yield variability and higher expected yield, and equity gains in disproportionately benefiting the most marginal group of farmers.

Pattern of solid paediatric malignant neoplasm at Lumhs, Jamshoro, Pakistan.

BACKGROUND: To evaluate pattern and frequency of solid malignant tumour in paediatric age group in our region. METHODS: A retrospective study of 113 patients, whose surgical biopsies submitted in histopathology section of Pathology department, LUMHS Jamshoro from January 2001 to December 2005. RESULTS: Total of 113 cases, 61 male and 52 female children in age group from 4 months to 15 years were diagnosed as solid malignant tumour with M/F ratio of 1.79:1 and mean age of 6.6 year. Maximum no. of patients was in 0-4 age 50.4%, followed by 32.7% in 4-9 and 16.8% in 10-15 years. The five most common tumours were Retinoblastoma 38.9%, Wilm's tumour 13.2%, Brain tumour (Glial tumours) 10.6%, Hodgkin disease 9.7% and soft tissue sarcomas 9.7%. Retinoblastoma and Wilm's tumour were common in 0-4 year age group, where as rest of tumour were more frequent in 5-9 and 10-15 years age group. Brain tumours and soft tissue sarcomas were common in females, while Hodgkin's disease was more common in males. CONCLUSION: Retinoblastoma was most common solid malignant tumour in early age group. It calls for ophthalmologic screening of all children below 1 year and high risk children until the age of 7 year, in order to detect retinoblastoma as early as possible.