AfricaRice Genetic Diversity and Improvement Program
Permanent URI for this collectionhttps://hdl.handle.net/10568/101108
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Item Performance of phenomic selection in rice: Effects of population size and genotypeenvironment interactions on predictive ability(Journal Article, 2024-12-23) de Verdal, H.; Segura, V.; Pot, D.; Salas, N.; Garin, V.; Rakotoson, T.; Raboin, L.M.; VomBrocke,K.; Dusserre,J.; Pacheco, S.A.C.Phenomic prediction (PP), a novel approach utilizing Near Infrared Spectroscopy (NIRS) data, offers an alternative to genomic prediction (GP) for breeding applications. In PP, a hyperspectral relationship matrix replaces the genomic relationship matrix, potentially capturing both additive and non-additive genetic effects. While PP boasts advantages in cost and throughput compared to GP, the factors influencing its accuracy remain unclear and need to be defined. This study investigated the impact of various factors, namely the training population size, the multi-environment information integration, and the incorporations of genotype x environment (GxE) effects, on PP compared to GP. We evaluated the prediction accuracies for several agronomically important traits (days to flowering, plant height, yield, harvest index, thousand-grain weight, and grain nitrogen content) in a rice diversity panel grown in four distinct environments. Training population size and GxE effects inclusion had minimal influence on PP accuracy. The key factor impacting the accuracy of PP was the number of environments included. Using data from a single environment, GP generally outperformed PP. However, with data from multiple environments, using genotypic random effect and relationship matrix per environment, PP achieved comparable accuracies to GP. Combining PP and GP information did not significantly improve predictions compared to the best model using a single source of information (e.g., average predictive ability of GP, PP, and combined GP and PP for grain yield were of 0.44, 0.42, and 0.44, respectively). Our findings suggest that PP can be as accurate as GP when all genotypes have at least one NIRS measurement, potentially offering significant advantages for rice breeding programs, reducing the breeding cycles and lowering program costs.Item Does Adoption of Improved Variety Encourage Farmers to Invest in Modern Inputs and Use Good Practices? Evidence from Rice Farmers in Guinea(Journal Article, 2024-10-14) Arouna, A.; Barry, M.L.; Kamano, P.; Yabi, J.A.Iron toxicity is one of the constraints limiting rice production in Africa. This study used a randomized controlled trial to assess the impact of an iron toxicity-tolerant variety, named ARICA 6, on different outcomes and investment in modern inputs by smallholder farmers. Two rounds of data were collected from 520 rice-farming households in Guinea. Results showed that the use of ARICA 6 increased rice yield by 330 kg ha−1 and net income by US$ 120 ha−1 . However, adoption of improved variety may not be enough to crowd in investment in modern inputs because farmers face other constraints.Item Identifcation of quantitative trait loci for salinity tolerance in rice (Oryza sativa L.) through Sahel 328/NERICA‑L‑9 mapping population at seedling stage(Journal Article, 2024-08-17) Sock, M.; Diouf, D.; Amoah, N.K.A; Bok‑Lee, S.; Manneh, B.; Bimpong, I.B.Abstract Rice (Oryza sativa L) is one of the most important staple food worldwide with a global production estimated at around 800 million metric tons for paddy rice in 2021. However, this production is hampered by several factors, such as land salinity. In this study, 230 F2:3 lines of the Sahel 328/NERICAL-9 mapping populations were evaluated for their tolerance to salinity at the young seedling stage at an electrical conductivity (EC) equivalent to 12 dSm−1. All parameters investigated were negatively affected under saline conditions compared to the control. Of these lines, 10 had a salt injury score (SIS) lower than that of the tolerant control, FL478 and 17 than the donor parent NERICA-L-9. About 4684 informative SNPs and 230 lines were used to construct the genetic linkage map. Twenty quantitative trait loci (QTLs) with LOD>3 that were related to SIS, root length, and shoot length were identified in this study. Twelve new QTLs associated with salt tolerance, qLR2.1, qLR2.2, qLR3.1, qLR3.2, qLR3.3, qLR5, qLR7.4, qLR10, qLR11, qLF6, qSES10 and qSES12, located on chromosomes 2, 3, 5, 7, 10, 11 and 12, respectively were discovered in this study. These QTLs were mapped on the 12 linkage groups (LG), with LG9 having the lowest number of molecular markers (160 SNPs), while LG2 was the largest with 498 markers. These markers may be useful in rice breeding programs.Item Identification of African rice genotypes with early morning flowering trait to avoid heat stress(Journal Article, 2024-09-23) Vimal, S.; Kora, O.K.; Koichi, F.; Venuprasad, R.Early morning flowering (EMF) is a desirable trait in rice to avoid heat stress as temperatures in early morning hours are low compared to afternoon and flowering is the most sensitive stage to heat exposure. Cultivated rice accessions including both Oryza glaberrima and O. sativa were phenotyped for an EMF trait in 2016–2018 in two locations viz. Cotonou in Benin Republic and Ibadan in Nigeria. The initial screening was done in Cotonou in three phases in 2016 dry season, 2017 wet season and 2017 dry season, respectively. The 2093 accessions used in initial screening were subdivided into three groups based on flowering duration ensuring that each accession was grown under conditions which were best suited to their flowering duration. Further screening was done in Ibadan in 2018 dry season and 2018 wet season. Out of 2093 accessions taken in the initial screening only 1754 accessions germinated out of which only 64 accessions exhibited EMF phenotype consistently across the cultivated years, seasons and locations. Among the 64 accessions exhibiting EMF phenotype, 15 accessions also showed an early peak in spikelet opening time (EPSOT) trait, more than 80% flowering before 09:00 h. We conclude that 15 O. glaberrima accessions identified possessing both the EMF and EPSOT traits are suitable donors for use in breeding for heat escape in rice.Item Adaptation And Selection of Early Maturing And High-Yielding Production of Some Exotic Rice Genotypes Under Egyptian Conditions(Journal Article, 2024) El-Badawy, O.A.; Soltan,S.A.; Bleih, M.E.; Anis, G.B.; Taha, A.S.; EL -Namaky, R.A.successive seasons during 2020 and 2021 at the Experimental Farm of Sakha Agricultural Research station, Sakha, Kafr El-Sheikh, Egypt, for identify and select the desirable early and high grain yield promising genotype under Egyptian conditions. Analysis of variance showed highly and significant differences among rice genotypes for all the studied traits. Grain yield of most rice genotypes was higher than check cultivars, the desirable genotypes, AFR0280, AFR278-2-2 and AFR278-8 recorded highest grain yield, 14.26, 14.03 and 14.00 (t/ha), respectively during seasons, genotypic and phenotypic coefficient of variation (PCV) were observed greater than environmental coefficient of variation as well as, high values of heritability (>85%) was observed for all studied characters, indicated to superior the genetic control for the expression to the studied characters and could be suggest that, these traits can be enhance through direct selection. Grain yield was positively and strongly correlated with each of plant he