The present investigation was planned to assess the principal component for yield, yield contributing traits and quality traits in thirty genotypes of rice suitable for aerobic condition. The genotypes were procured from Directorate of Rice Research, Hyderabad and were evaluated in randomized block design with three replication. Principal component analysis (PCA) indicated that three components (PC1 to PC3) accounted for about 78.809% of the total variation among traits. Out of total principal components retained PC1, PC2 and PC3 with values of 58.125%, 13.305% and 7.380% respectively contributed more to the total variation. The first principal component had high positive loading for 7 characters out of 18 viz.grain yield per plant (0.278), canopy temperature (0.278), 1000-grain weight (0.271), panicle length (0.270), critical temperature for reproductive stage (0.239), seedling vigour (0.213) and days to 50% flowering per plant (0.201) which contributed more to the diversity. Genotypes in cluster VI showed higher mean performance for most of the yield attributing characters. Therefore, selection of parents from this cluster for these traits would be effective. The result of present study could be exploited in planning and execution of future breeding programme in rice under aerobic condition.
An investigation was carried out with forty greengram genotypes including one check Samrat during summer 2015 to find out suitable selection indices for influencing the performance of genotypes under heat stress. Seed yield showed positive and significant association with days to maturity (DM), growing degree days (GDD), relative temperature depression (RTD) and heat use efficiency (HUE). Stepwise regression analysis showed that maximum contribution was made by HUE followed by photothermal index (PTI) and DM. This indicated that HUE might be utilized as primary key factor, whereas PTI, DM and RTD might be utilized as secondary key factor for improving heat tolerance in greengram. The comparison of different functions revealed that among the single character selection index HUE (index IV) was the key component to construct selection index for terminal heat tolerance in greengram. Besidethis DM, PTI, RTD, HUE and seed yield per plant (SYP) (index XV) should be simultaneously selected to achieve maximum gain and improve the heat tolerance in greengram.
The present investigation for various genetic parameters was done for twenty-two lowland rice genotypes in R.C.B.D. with three replications at Rice Breeding Section, Pusa Farm, Dr. Rajendra Prasad Central Agricultural University, Pusa, Samastipur, Bihar. Analysis of variance revealed significant differences (P-value =0.01) among genotypes for all the characters. Brasali was the highest yielder suggesting that it can be used for crossing programme for improvement in yield. The phenotypic variance was higher than corresponding genotypic variances for all the characters studied. Genotypic coefficient of variation (GCV) and phenotypic coefficient of variation (PCV) were highest for grain yield per plant followed by1000 grain weight, plant height, number of panicles, root volume, leaf length and days to 50 % flowering revealing that sufficient variability was present in the gene pool for these characters. Thus, there is ample scope for genetic improvement of these traits through selection. The broad sense heritability ranged from 23 % (panicle length of main axis) to 97% (1000 grain weight). High heritability was obtained for most of the characters except for panicle length of main axis and kernel width. High heritability accompanied with high genetic advance as percent of mean was recorded for days to 50% flowering, plant height, root volume, number of panicles, 1000 grain weight, leaf length and grain yield per plant. High values of GCV, PCV, heritability and genetic advance as percent of mean observed for various characters indicate that these traits can be used as selection indices for yield improvement.
The present investigation was carried out including 10 parents and their 45 half diallel crosses with the objective to study the relationship between heterosis and diverse genotype. The Mahalonobis D2values resulted in grouping of 10 parents into 3 clusters. Cluster I was comprised of four genotypes, cluster II comprised of five genotypes while, cluster III was found monogenotypic. Cluster II and Cluster III had maximum mean values for 4 traits. Highest intercluster distance was also observed in these 2 cluster followed by cluster I and III . Maximum intra cluster distance was observed in cluster II followed by cluster I. The highest contribution in the manifestation of total genetic divergence was exhibited by grain iron content followed by grain zinc content. The relationship between parental diversity and heterosis indicated that majority of crosses belong to moderate divergence class. The cross P4×P5 exhibiting better parent heterosis for maximum traits also exhibited at par mean performance for 5 traits including grain yield per plant over the better parent. For grain zinc content, two crosses from high and low while, nine crosses from moderate divergence classes reported positive significant heterosis and SCA effects. For grain iron content, 1 cross with high, 2 crosses with moderate while four crosses with low divergence classes reported significantly positive heterosis and SCA effects.
A field experiment was carried out at Dr. Rajendra Prasad Central Agricultural University, Pusa, Samastipur during Rabi season, 2021–22. The experiment was conducted using a split plot design with three varieties of fodder oat (Kent, JHO-822 and Local) in main-plots and four different sowing dates (15th November, 25th November, 5th December and 15th December) in sub-plots with three replications. The results obtained from the experiment showed that ‘JHO-822’ recorded 9.4 and 29.5% higher green and dry fodder yield than local variety and accumulated the highest meteorological indices (GDD, HTU and PTU) and resulted in the highest HUE and PTUE. Among different micro-environments, seeding on 15th November recorded the highest green and dry fodder yield with substantially greater values of agro-meteorological indices which decreased with advancement of sowing date. Per day delay in sowing resulted in 0.7% decrease in green fodder yield and 1.2% decrease in dry fodder yield.
Boro rice cultivation is a special system of rice cultivation in low productive, waterlogged, low-lying deepwater land during November-May in eastern India. In such land, neither kharif (Jul-Oct) rice nor rabi (Nov-Apr) wheat is successful because of excess water. The boro crop is usually sown in November and transplanted when the temperature starts rising from January onward. The average minimum temperature during this period varies from 8 to 12°C. Crop productivity is very high (Thakur and Mishra 1990); consequently, boro rice has become popular in Bihar and eastern Uttar Pradesh. The suitability of rice varieties for boro cultivation mainly depends on their germination, tolerance for low temperature at the seedling stage, and seedling vigor.
Using 15 sweet corn inbreds, a line x tester design was made to perform combining ability analysis for yield and its contributing traits. For every character under study, the interaction between Line x Tester was highly significant, with the exception of days to 50% tasseling. For every attribute studied, the variation resulting from sca exceeded the variance resulting from gca. Which indicates the presence of non-additive gene action between the parents. As a result of their high per se performance combined with high gca effects for the majority of the yield and yield contributing traits, such as ear weight without husk, number of kernels per row, total soluble solids, 100 kernel weight, cob yield per plot and total sugar, the lines L6, L12 and testers T1, T2 were determined to be the best general combiners. The hybrid L3×T1, which had the highest per se performance and sca for cob yield per plot, 100 kernel weight and ear weight without husk, was determined to be the best hybrid out of the 36 hybrids examined.
The present investigation was carried out with 150 rice genotypes and three check varieties namely Rajshree, Pankaj and Rajendra Neelam with the view of assessing the variability in traits related to productivity and studying the response of these varieties towards brown spot resistance under the aerobic condition. These genotypes were evaluated for brown spot incidence and yield potential by recording observation for 11 quantitative traits by using augmented randomized complete block design at Rice research farm of RPCAU, Pusa, Bihar, during Kharif season of 2019. Analysis of variance revealed significant differences amongst the genotypes for all the eleven traits studied. Based on the mean performance, 14 genotypes out of 150 genotypes were significantly superior to the best check, Rajendra Neelam, for three traits viz., grain yield/ plant, Percent Disease Intensity (PDI) and area under disease progress curve (AUDPC), which are considered key traits for the assessment of brown spot incidence. The genotypes viz., VLD 16 entry no. -5, Udyagiri entry no.-9, and SKL 6 entry no.-94 significantly exhibited high mean for majority of the traits under study. Based on the AUDPC values, genotypes Satabdi, PS-4, Haryana Basmati and SKL6 were resistant for brown spot incidence. For most of the traits studied, moderate to low value of phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) was recorded. Higher magnitude of broad sense heritability and genetic advance as per cent of mean (GAM) were perceived for days to 50% flowering, plant height, no. of tillers per plant, no. of panicles per plant, filled grains per panicle, grain yield per plant, PDI, AUDPC signifying that direct selection by these traits can be rewarding for achieving yield improvisation and resistance to brown spot disease
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