Development of Provitamin A quality protein maize (PVA-QPM) conferring resistance to maize streak virus (MSV) would reduce the prevalence of the disease, alleviate malnutrition and increase food security in sub-Saharan Africa. This study was conducted to (i) evaluate early maturing PVA-QPM inbreds and their derived testcross hybrids for grain yield, MSV-resistant, carotenoids, and tryptophan contents, (ii) estimate the combining ability of the MSV-resistant PVA-QPM testcrosses for all traits. Five improved open-pollinated MSV resistance cultivars and five early maturing PVA-QPM inbreds were crossed in a half-diallel fashion without reciprocals. The derived forty-five F1 topcrosses, ten parental materials, and two commercial hybrids that served as controls were tested at the Lower Niger River Basin Development Authority in Oke-Oyi, Nigeria, during rain-fed of the year 2019 and 2020. The PVA-QPM inbreds from TZEIORQ 13, TZEIORQ 29, and TZEQI 82 that were crossed with MSV resistance AK-9528-DMRSR and Pop 28 SR appeared potentially useful combinations for enhancing grain yield, MSV-resistant, carotenoids, and tryptophan contents, Testcrossed TZEQI 82 × AK-9528-DMRSR POP 28 SR, TZEQI 82 × ACR. 91 SUWAN-1-SR C1 and TZEQI 82 × IK.91 TZL COMP 3-Y C1 were most outstanding for all measured grain yield and nutrient contents. Additive genetic effects were preponderant over non-additive genetic effects under artificial infection of MSV disease. These three promising MSV resistance PVA-QPM hybrids should be evaluated under on-farm multiplication trials for stability performance and adaptation to reduce malnourishment and food self-sufficiency in SSA. Also, further researches on genomic analyses of the superior testcrosses are desirable.
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Genetic variability and correlation analysis are fundamental references for the innovative development of breeding programs to improve varieties and desirable traits. In the present study, the correlation and path analysis was conducted to understand the association among yield, micronutrients (iron and zinc), and protein content under aerobic conditions in local rice landraces from various agro ecological regions of Karnataka, India. The grain yield per plant showed a significant positive correlation with plant height, the tiller number, spikelet fertility, flag leaf length, and test weight. The zinc content was negatively correlated with grain yield per plant. The phenotypic path-coefficient analysis revealed that the total number of tillers, grain length, test weight, and harvest index exhibited a positive direct effect on grain yield per plant, while Grain protein content showed a low direct effect on this trait. This study also indicated that harvest index, flag leaf length, spikelet fertility, and test weight could be considered to make for a higher yield.
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A two-year factorial arranged field experiment in randomized complete block design with three replications was carried out in 2014 and 2015 at Michael Okpara University of Agriculture Teaching and Research Farm, Umudike (latitude 05° 29′N; longitude 07° 33′E; altitude 122 m above sea level), Nigeria. The
objective
s were to assess growth and yield response of twenty newly released cowpea genotypes to different planting dates (July, August and September). Plant height, number of leaves/plant, number of branches/plant, shoot biomass, total dry matter, number of nodules/plant, weight of pod, number of seeds/pod, seed weight/pod and grain yield varied amongst the genotypes and across the different planting dates in both years. The association between grain yield and other variables analysed across both years was significant and positive except 100-seed weight and the phenological characters of the plant. Path coefficients analysis across two years indicated that seed weight/pod followed by number of branches/plant and number of seeds/pod had positive direct effect on grain yield of cowpea in contrast to characters that exhibited negative but direct effect on yield. The other traits had relatively negligible to low indirect effects that were positive through other component traits. The grain yield sequence of interaction between genotype and date of planting was in this order: IT06K-141 planted in July > IT11K-61-82 planted in September > IT99K-573-1-1 planted in August. IT06K-141 genotype was considered to be better endowed genetically while the mean across both years indicated August as appropriate planting date to ensure high and sustainable grain yield.
Aggregate selection helps making selection decisions for improved profitability and permits to exploit information on correlated traits to improve accuracy. In the present study, the efficiency of trait selection was assessed by the Smith-Hazel (SHI) and the Pesek-Baker (PBI) models in 35 wheat genotypes under drought stress at heading and well-irrigated conditions at the Research Farm of Shiraz University, Iran in 2011 and 2012 years. The analysis of correlated response (CR) revealed that thousand grain weight (TGW) with CR = 24.05 (in 2011) and 9.15 (in 2012) and harvest index (HI) with CR = 18.37 (in 2011) and 9.08 (in 2012) had higher indirect effects on grain yield (GY) increase under drought stress. In both years, biological yield (BY), grain number/spike (GN), TGW, and GY had the highest genetic gain (
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Eight advanced breeding lines of cowpea [
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Increasing demand for food commodities and energy supply highlight the necessity to further improve crop productivity. At the Plant and Animal Genome Conference (PAG XXIV), recent developments and future plans for genomics research of plants and animals were presented. PAG XXIV provided a forum to explore crop genomes with the aim of providing new opportunities for crop breeding and the foundation for functional genomic studies to improve agriculture production and help feed the growing population. Genetic diversity and population structure studies of crops have allowed us to explore alleles related to different characteristics important for plant breeding. Several useful databases were introduced in PAG XXIV. They were developed to integrate a growing set of commonly used data types and analysis tools with new capabilities for visualization, exploration, and predictive analysis. This review highlights the global trends in plant genomics presented at PAG XXIV by focusing on crop productivity.
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