Information about the amount and distribution of genetic variation in germplasm collections is important for their efficient management and effective utilization in plant breeding. Therefore this study was conducted t...Information about the amount and distribution of genetic variation in germplasm collections is important for their efficient management and effective utilization in plant breeding. Therefore this study was conducted to assess genetic diversity of sugarcane germplasm in Ethiopia. An experiment comprising of 400 sugarcane genotypes (174 local and 226 introduced) was conducted between March 2012 and October 2013 at Wonji and Metehara Sugar Estates using partial balanced lattice design with two replications. Data was recorded on 21 quantitative characters which included cane yield and its components, sugar yield and sugar quality traits. ANOVA portrayed highly significant differences (P < 0.01) among the genotypes for 21 quantitative traits. Cluster analysis revealed intra cluster D<sup>2 </sup>values ranging from 2.16 - 10.60 and inter cluster from 7.24 - 5864. There were six principal components accounting for 79.26% of the total variation in the tested materials. Millable stalk count, single cane weight, stalk diameter, cane yield, sugar yield and sugar quality traits showed high positive loading on the first two PCs and accounted for most of the variation observed among the genotypes. Therefore, this study suggested that the important characters responsible for diversity in the sugarcane genotypes could be grouped in two principal components namely “Yield” and “Quality” with “Yield” traits being comparatively more important than “Quality”. Genotypes clustered for high mean values of various traits could be exploited for further improvement of the crop either through selection or through hybridization. The clusters having high mean value for yield could be selected for yield per se as well.展开更多
This study evaluated the genetic and agronomic parameter estimates of maize under different nitrogen rates. The trial was established at the Njala Agricultural Research Centre experimental site during 2021 and 2022 in...This study evaluated the genetic and agronomic parameter estimates of maize under different nitrogen rates. The trial was established at the Njala Agricultural Research Centre experimental site during 2021 and 2022 in a split block design with three maize varieties (IWCD2, 2009EVDT, and DMR-ESR-Yellow) and seven nitrogen (0, 30, 60, 90, 120, 150 and 180 kg∙N∙ha<sup>−</sup><sup>1</sup>) rates. Findings showed that cob diameter and anthesis silking time (ASI) had intermediate heritability, ASI had high genetic advance, ASI and grain yield had high genotypic coefficient of variation (GCV), while traits with high phenotypic coefficient of variation (PCV) were plant height, ASI, grain yield, number of kernel per cob, number of kernel rows, ear length, and ear height. The PCV values were higher than GCV, indicating the influence of the environment in the studied traits. Nitrogen rates and variety significantly (p < 0.05) influenced grain yield production. Mean grain yields and economic parameter estimates increased with increasing nitrogen rates, with the 30 and 180 kg∙N∙ha<sup>−</sup><sup>1</sup> plots exhibiting the lowest and highest grain yields of 1238 kg∙ha<sup>−</sup><sup>1</sup> and 2098 kg∙ha<sup>−</sup><sup>1</sup>, respectively. Variety and nitrogen effects on partial factor productivity (PFP<sub>N</sub>), agronomic efficiency (AEN), net returns (NR), value cost ratio (VCR) and marginal return (MR) indicated that these parameters were significantly affected (p < 0.05) by these factors. The highest PFP<sub>N</sub> (41.3 kg grain kg<sup>−</sup><sup>1</sup>∙N) and AEN (29.4 kg grain kg<sup>−</sup><sup>1</sup>∙N) were obtained in the 30 kg∙N∙ha<sup>−</sup><sup>1</sup> plots, while the highest VCR (2.8) and MR (SLL 1.8 SLL<sup>−</sup><sup>1</sup> spent on N) were obtained in the 180 kg∙N∙ha<sup>−</sup><sup>1</sup>. The significant influence of variety and nitrogen on traits suggests that increasing yields and maximizing profits require use of appropriate nitrogen fertilization and improved farming practices that could be exploited for increased productivity of maize.展开更多
文摘Information about the amount and distribution of genetic variation in germplasm collections is important for their efficient management and effective utilization in plant breeding. Therefore this study was conducted to assess genetic diversity of sugarcane germplasm in Ethiopia. An experiment comprising of 400 sugarcane genotypes (174 local and 226 introduced) was conducted between March 2012 and October 2013 at Wonji and Metehara Sugar Estates using partial balanced lattice design with two replications. Data was recorded on 21 quantitative characters which included cane yield and its components, sugar yield and sugar quality traits. ANOVA portrayed highly significant differences (P < 0.01) among the genotypes for 21 quantitative traits. Cluster analysis revealed intra cluster D<sup>2 </sup>values ranging from 2.16 - 10.60 and inter cluster from 7.24 - 5864. There were six principal components accounting for 79.26% of the total variation in the tested materials. Millable stalk count, single cane weight, stalk diameter, cane yield, sugar yield and sugar quality traits showed high positive loading on the first two PCs and accounted for most of the variation observed among the genotypes. Therefore, this study suggested that the important characters responsible for diversity in the sugarcane genotypes could be grouped in two principal components namely “Yield” and “Quality” with “Yield” traits being comparatively more important than “Quality”. Genotypes clustered for high mean values of various traits could be exploited for further improvement of the crop either through selection or through hybridization. The clusters having high mean value for yield could be selected for yield per se as well.
文摘This study evaluated the genetic and agronomic parameter estimates of maize under different nitrogen rates. The trial was established at the Njala Agricultural Research Centre experimental site during 2021 and 2022 in a split block design with three maize varieties (IWCD2, 2009EVDT, and DMR-ESR-Yellow) and seven nitrogen (0, 30, 60, 90, 120, 150 and 180 kg∙N∙ha<sup>−</sup><sup>1</sup>) rates. Findings showed that cob diameter and anthesis silking time (ASI) had intermediate heritability, ASI had high genetic advance, ASI and grain yield had high genotypic coefficient of variation (GCV), while traits with high phenotypic coefficient of variation (PCV) were plant height, ASI, grain yield, number of kernel per cob, number of kernel rows, ear length, and ear height. The PCV values were higher than GCV, indicating the influence of the environment in the studied traits. Nitrogen rates and variety significantly (p < 0.05) influenced grain yield production. Mean grain yields and economic parameter estimates increased with increasing nitrogen rates, with the 30 and 180 kg∙N∙ha<sup>−</sup><sup>1</sup> plots exhibiting the lowest and highest grain yields of 1238 kg∙ha<sup>−</sup><sup>1</sup> and 2098 kg∙ha<sup>−</sup><sup>1</sup>, respectively. Variety and nitrogen effects on partial factor productivity (PFP<sub>N</sub>), agronomic efficiency (AEN), net returns (NR), value cost ratio (VCR) and marginal return (MR) indicated that these parameters were significantly affected (p < 0.05) by these factors. The highest PFP<sub>N</sub> (41.3 kg grain kg<sup>−</sup><sup>1</sup>∙N) and AEN (29.4 kg grain kg<sup>−</sup><sup>1</sup>∙N) were obtained in the 30 kg∙N∙ha<sup>−</sup><sup>1</sup> plots, while the highest VCR (2.8) and MR (SLL 1.8 SLL<sup>−</sup><sup>1</sup> spent on N) were obtained in the 180 kg∙N∙ha<sup>−</sup><sup>1</sup>. The significant influence of variety and nitrogen on traits suggests that increasing yields and maximizing profits require use of appropriate nitrogen fertilization and improved farming practices that could be exploited for increased productivity of maize.
