Number Of Filled Grains Panicle-1 Research Articles

Genetic Gain in Yield and Yield Attributing Traits of Rice under Upland Ecosystem of Fogera, Northwest Ethiopia

Evaluation of varieties from different years in a common environment is one of the most direct methods used to estimate breeding progress. Twenty upland rice varieties released in Ethiopia from 1998 to 2016 were evaluated at Fogera National Rice Research and Training Center in 2017 cropping season to estimate the amount of genetic gain over the years. The varieties were laid out in a randomized complete block design with three replications. Analysis of variance revealed significant differences among varieties for all traits. Grain yield was increased from 2.76 t ha-1 to 4.86 t ha-1 over the past 18 years. The average rate of increase in grain yield of upland rice per year, estimated from the linear regression on year of variety release, was 0.044 t ha-1 with a relative genetic gain of 1.59% year-1, although non-significant. The study showed significant improvements in grain-filling period, panicles length and number of filled-grains panicle-1. Significant reduction was also observed in days to heading and thousand-seed weight. No marked changes were observed in grain yield per plant and biological yield, number of fertile tillers, plant height and days to maturity over the 18-year period.

Phenotypic variation and correlation of traits in Philippine hybrid rice varieties

Understanding the phenotypic variation and correlation in hybrid rice varieties will lead to proper utilization of these genetic resources. Grain yield (GY), the primary trait, and its secondary traits such as days to 50% flowering (DF), days to maturity (DM), grain length (GL), grain weight (GW), number of filled grains panicle-1 (NFGP), one thousand grain weight (OTGW) panicle length (PL), panicle weight (PW), spikelet fertility (SF), and spikelet number panicle-1 (SNP) of 13 hybrid rice in two environments (E1 and E2) were analyzed using combined analysis of variance (ANOVA) and correlation analysis. High significant variation was found among hybrids (G) in all traits except for GW while there was at least significant result among environments (E) in DF, DM, GL, GW, PW, and OTGW, and in GxE in DF, DM, GW, NFGP, PW, and SNP. Therefore, E1 hybrids were early flowering and maturing, had longer, wider, and more grains, had longer panicles, and higher yield while in E2 hybrids were late flowering and maturing, and had heavier grains. However, among the 13 hybrid rice, M1 had the highest GY and GL in each environment with a mean of 9.57 t ha–1 and 9.75 mm, respectively. M1, therefore, can be recommended to farmers for varietal utilization. Correlation analysis, on the other hand, found 15 and 17 significant correlations in E1 and E2, respectively. Of the correlation results, it was found out that among the secondary traits, only NFGP was consistently, significantly and positively correlated with GY in two environments. The result implied that attaining higher yield in hybrid rice cultivation can be possible by giving more attention to the plants during the grain filling stage.
 J. Bangladesh Agril. Univ. 17(2): 179–186, June 2019

Heterosis studies for yield and agronomic traits in Thai upland rice

The exploitation of heterosis and heterobeltiosis are the promising way for raising yield potential in crops. Twenty-eight F1 hybrids and their eight parents were evaluated to estimate the heterosis and heterobeltiosis of yield and other agronomic traits in Thai upland rice. Significant differences of analysis of variance were observed for all studied traits, indicating the existence of worth genetic variability among the hybrids and their parents. The highest significant positive heterosis and heterobeltiosis was attained by Dawk Pa-yawm × Hawm Mali Doi for number of tillers (90.59%; 58.82%) and number of panicles plant-1 (60.35%; 46.14%), and panicle length (heterobeltiosis: 20.05%), but highest significant negative heterosis for plant height (-8.90%). Likewise, Nual Hawm × Khun Nan showed the highest significant positive heterosis and heterobeltiosis for yield components, viz., number of filled grains panicle-1 (57.39%; 52.25%), spikelet fertility (25.01%; 21.16%), 1000 grain weight (heterosis: 12.85%) and grain yield plant-1 (heterosis: 19.86%), but highest significant negative for days to flowering (-17.52%; -6.03%) and days to maturity (-12.00%; -4.91%). These crosses were recommended as the most promising combinations to gain early favorable segregants and developing high yielding upland rice hybrid varieties by heterosis breeding.