Ephemeral Growth span and Rapid Veg-repo shift is Critical for Survival against Naturally Rainfed Upland and Erratic Drought in Rice Growing Regions

Two experiments were undertaken simultaneously (early generation evalua-tion and advanced generation evaluation respectively) during Kharif 2013-14 at S G College of Agriculture and Research Station, Jagdalpur, IGKV, Raipur, Chhattisgarh, to indentify and analyze ephemeral genotypes for their suitability in rainfed upland and present era’s climate change-laid unpredicted water stress production agro-ecosystem. In early generation testing, mean plot flowering was recorded to be 72 Days After Sowing (DAS), plant height 83cm, panicles per square meter 212 and grain yield to be 2330kg/ha. Regional check Vandana and CRR-676-1 flowered earliest by 68 DAS followed by CRR-627-35-1-5 (69 DAS) and CRR-507-11-B-1 and CRR-605-23-1. The CRR-433-2-1-1 flowered latest by 83 DAS and as per hypothesis; yield was con-siderably reduced since plant could not develop optimum source-sink bal-ance and carbon accumulation in seeds eventually. Regarding, crop yield, five genotypes placed above the local check, namely CRR-597-5-1 (29.47%), the national check i.e. Anjali (21.05%), CRR-676-1 (15.79%), CRR-433-2-1-1 (10.53%) and the regional check i.e. Vandana (7.92%). Among advanced ma-terial, interestingly, the highest yielding genotype flowered earliest (69 DAS) that suggests the accomplishment of crop growth and physio-biochemical development while utilizing the soil and environmental reserve appropriate-ly. On overall, mean yield was 2349kg/ha, whereas genotype CRR-616-B-2-54-1 ranked 1st with 2718 kg/ha yield, 69 days of flowering duration and short bold grains. The bimodal experiment concludes that ephemeral growth span and rapid veg-repo shift is critical for survival against naturally rainfed-upland and erratic drought in rice growing regions and those genotypes which maintain the physiological buffer at the shift will be able to sustain genetic yield potential.

Early generation testing of common bean (Phaseolus vulgaris L.) populations in sole crop and in maize/bean intercrop

Few plant-breeding studies have examined methodology for improving common bean (Phaseolus vulgaris L.) yields by selecting in an intercrop situation. We hypothesized that early-generation testing would be as useful in a maize (Zea mays L.)/bean intercrop as in sole crop for identifying superior bean populations for yield. F2 to F5 bulks of six selected crosses and their F5-derived advanced lines were evaluated in sole crop or intercrop. The F2 and F5 bulks were evaluated together in a preliminary trial in one location, while the advanced lines were evaluated with the F3s in one location, and with the F4s in two locations. Within sole crop, selection of the best three populations, based on F2 performance, provided 67% of the top advanced lines. The rank correlation between average bulk yield across generations and the average line yield was positive and significant. Within intercrop, selection of the best three populations provided 56% of the top advanced lines. The rank correlation between advanced line yield and bulk yield across generations was positive but not significant. Also, the top three F2 populations selected in sole crop produced 89% of the top advanced lines in intercrop. Advanced line performance showed a positive significant correlation with mean F4 bulk performance for grain yield, 100-seed weight and seeds per pod within sole crop, while positive significant correlation was seen with pods per plant and seeds per pod in intercrop. Results indicate that F2 bulk yields can be used to discard the least promising crosses in both cropping systems. Key words: Early generation testing, Phaseolus vulgaris, intercropping

Combined selection in early generation testing of self-pollinated plants

Seven selection indexes based on the phenotypic value of the individual and the mean performance of its family were assessed for their application in breeding of self-pollinated plants. There is no clear superiority from one index to another although some show one or more negative aspects, such as favoring the selection of a top performing plant from an inferior family in detriment of an excellent plant from a superior family

The Effectiveness of Early Generation Testing as Applied to a Recurrent Selection Program in Peanut1

The effectiveness of early generation testing for yield improvement in peanut (Arachis hypogaea L.) was evaluated in an attempt to increase the efficiency of an on-going recurrent selection program by reducing the time required for evaluation and selection. The objectives of the study were to (1) determine if the number of years required per cycle of selection could be reduced; and (2) estimate the amount of genetic variability remaining in the population for yield and four agronomic traits after four cycles of recurrent selection. Sixty-eight random-mated crosses, among the 40 highest yielding lines from the cycle 3 population, were evaluated for yield and agronomic traits in 1985 (S0:1), 1986 (S0:2), and 1987 (S0:3). The results were compared to determine if early generation performance accurately predicts the performance of cross bulks in later generations. No significant correlations were found for yield of entries in the S0:3 and S0:2 or in the S0:3 and S0:1; however, there was a significant correlation between yield of entries in the S0:2 and S0:1 generations. No correlations were found between yield and any of the agronomic traits measured in the S0:3; however, significant correlations were found in the S0:2 between yield and most traits measured. Significant correlations were also found for entries in the S0:3 and S0:2 generations for each agronomic trait measured except number of seed per 20 pods. Early generation testings appears to be useful for selection of certain agronomic traits, but of limited value when selecting for yield. A decrease in genetic variation for yield in the population from the S0:1 to the S0:3 generation was observed; however, the number of crosses equal to or exceeding the yield of the check cultivar increased in later generations. All agronomic traits measured, except number of seed per 20 pods, showed significant genetic variation remaining in the population in both the S0:2 and S0:3 generations. The greater the genetic variation remaining in the population for a given trait, the more likely it is that further improvement of that trait will be realized with additional cycles of selection.