The Effects of Weed Residue Management on Pests, Pest Damage, Predators and Crop Yield in Upland Rice in Côte d'Ivoire

AbstractIn temperate climates, densities of plant-parasitic nematodes at or shortly before sowing are a useful predictor of their damage potential. Re-examination of data from nematode communities on upland rice in Côte d'Ivoire showed that interpretation of nematode pest potentials and the damage caused by either individual species, or by the community as a whole, is less simple. The numerical proportion of individual nematode species within a plant-parasitic nematode community, comprising Heterodera sacchari, Pratylenchus zeae , Meloidogyne incognita, Helicotylenchus dihystera, Mesocriconema tescorum and Xiphinema spp., changed with duration of the cropping cycle. The relative importance to the crop of the different species changed with time, and with development of the community structure over the course of the season. Analysis suggested that for H.sacchari, the mid-season population densities were most highly correlated with crop damage (yield loss) and therefore its damage potential for that particular season. The pest potential of other known rice pest species, such as M. incognita and P.zeae, was likely indicated earlier in the season, but the population increase of other nematode species in the community, particularly H. sacchari, compounded the interpretation of the data for other species. The use of single linear regression to assess the importance of individual nematode species conflicted with results of analyses using multiple stepwise regression, while use of cluster analysis permitted the identification of species groups at early and late stages in the cropping season.

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New drought-tolerant rainfed upland rice (Oryza sp.) genotypes adapted to the west, centre-west, and centre regions of Côte d'Ivoire

Journal of Agricultural and Crop Research ◽

10.33495/jacr_v8i12.20.202 ◽

2020 ◽

Vol 8 (12) ◽

pp. 289-296

Author(s):

Noumouha Ghislain ◽

◽

Anguété Kouamé ◽

Bouet Alphonse ◽

Bahan Frank ◽

...

Keyword(s):

Cote D'ivoire ◽

Côte D’Ivoire ◽

Upland Rice ◽

Environment Interaction ◽

Gge Biplot ◽

The West ◽

Cote D’Ivoire ◽

Côte D'ivoire ◽

Rainfed Upland ◽

Paddy Yield

To select new rainfed upland rice genotypes, adapted to the West, Centre-West, and Centre regions of Côte d'Ivoire, a study was conducted in research stations. Six genotypes (ART15-11-8-5-2-B-1, WAB891-SG12, WAB1092-B-40AB.1, ARCC3Fa3L10P1-1-B-1, and ART15-16-12 -3-1-B-1-B-3-1) including the control IDSA 10, widely cultivated across the country, were evaluated on three research stations of the National Center of Agricultural Research (CNRA), during the wet seasons of the year 2016 and 2017. These stations are located at the West, Center, and West-Center of Côte d'Ivoire. The trial was set up in a randomised complete block design with four replications. The agromorphological traits such as tillering ability, sowing-50% heading cycle, plant height, percentage of productive tillers, sowing-maturity cycle, and paddy yield were collected for each genotype. In all the environments evaluated, the genotypes ART15-11-8-5-2-B-1, WAB891-SG12, ARCC3Fa3L10P1-1-B-1, and ART15-16-12-3-1-B-1-B -3-1 were characterised by high percentages of productive tillers (87 to 91%), intermediate plant heights (114 to 121 cm), and high average paddy yields (2,601 to 2,810 kg/ha). Yield gains of these genotypes compared to the control ranged from 16 to 25%. The Genotype × Environment interaction (G × E) was highly significant for paddy yield (p < 0.001). The study of the interaction based on the first two principal components analysis of the GGE biplot, explained a 97% of the main effect of the Genotype and the G × E interaction. The polygon tool of the biplot suggested the existence of a single complex mega-environment. Visualizing the mean and stability of genotypes' paddy yield in the biplot indicated that genotypes ART15-11-8-5-2-B-1, WAB891-SG12, ARCC3Fa3L10P1-1-B-1, and ART15-16-12-3-1-B-1-B- 3-1 were more adapted to upland rice-growing regions of the West, Center-West, and Center of Côte d'Ivoire. These genotypes can be released for large scale rice production in these regions. Keywords: Rainfed upland rice, G × E interaction, GGE biplot analysis

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Heterodera sacchari: field population dynamics and damage to upland rice in Côte d'Ivoire

Nematology ◽

10.1163/156854100509466 ◽

2000 ◽

Vol 2 (5) ◽

pp. 541-550 ◽

Cited By ~ 7

Author(s):

Daniel Coyne ◽

Richard Plowright

Keyword(s):

Oryza Sativa ◽

Grain Yield ◽

Cote D'ivoire ◽

Côte D’Ivoire ◽

Upland Rice ◽

Population Densities ◽

Cote D’Ivoire ◽

Crop Height ◽

Côte D'ivoire ◽

Egg Density

Abstract In field studies in Côte d'Ivoire, West Africa, Heterodera sacchari severely reduced upland rice (Oryza sativa cv. IDSA6) grain yield. In 1995, pre-sowing treatments with carbofuran did not affect crop height, number of tillers at 84 days after sowing (DAS) nor grain yield of O. sativa cv. IDSA6 or O. glaberrima cv. CG14. The protection of eggs within cysts and a delayed hatching pattern are thought to have contributed to this. In 1996 and 1997, cultural methods were used to modify initial population densities and grain yield was correlated negatively with mid-season (56 and 84 DAS) H. sacchari population densities. The relationship between yield (Y) and population densities at 56 DAS was described by the equation Y = Ymean.Ymin + Ymean(1 - Ymin).z(P-T). The crop tolerance limit at 56 DAS was calculated as 1.67 and 2.39 eggs/cm3 soil, and z as 0.15 and 0.65 in 1996 and 1997, respectively. Population densities of H. sacchari at sowing, 28 DAS, 42 DAS and harvest were not correlated with grain yield in regression analysis of individual plots, but grain yield was significantly greater in groups of plots which had lowest initial egg density. Initial egg population densities were correlated negatively with leaf area index at 84 and 96 DAS in 1996 and 1997, respectively, with implications for growth of and competition from weeds. In 1997, mean initial egg density was 63% more and mean yield 57% less than in 1996. Drought in 1997 exacerbated yield losses. In 1996 and 1997, crop height, number of tillers and relative leaf chlorophyll content were significantly less in plots with higher mean egg density at sowing. Heterodera sacchari: dynamique des populations au champ et dommages causés au riz de plateau en Côte d'lvoire - Des études au champ menées en Côte d'lvoire (Afrique de l'Ouest) ont montré qu' Heterodera sacchari diminue de façon importante la récolte en grain du riz de plateau (Oryza sativa cv. IDSA6). En 1955, un traitement avant semis au carbofuran n'a pas influé sur la hauteur des pieds, ni sur le nombre de chaumes, non plus que sur la récolte en grain d' O. sativa cv. IDSA6 ou d' O. glaberrima cv. CG14, cela 84 jours après le semis (JAS). La protection apportée aux œufs par les kystes ainsi qu'un type d'éclosion différée sont supposés avoir contribué à ce phénomène. En 1996 et 1997, les méthodes culturales adoptées ont permis de modifier la densité des populations initiales; de ce fait la récolte en grain s'est trouvée corrélée négativement, à la mi-saison (56 et 84 JAS), avec la densité des population d' H. sacchari . La relation entre la récolte (Y) et la densité de la population à 56 JAS est définie par l'équation: Y = Ymoy.Ymin + Ymoy(1 - Ymin).z(P-T). Le calcul de la limite de tolérance à 56 JAS donne des chiffres de 1,67 et 2,39 œufs/cm3 et une valeur de z de 0.15 et 0.65 pour 1996 et 1997, respectivement. Une analyse de régression - portant sur les parcelles individuelles - entre densité des populations à 28 et 42 JAS et à la récolte n'a pas montré de corrélation avec le niveau de la récolte en grain; cependant, cette récolte était significativement plus élevée dans le groupe des parcelles où la densité initiale des œufs était la plus faible. Ces densités initiales d'œufs sont corrélées négativement avec l'indice de surface foliaire à 84 et 96 JAS, en 1996 et 1997 respectivement, cela ayant certaines implications dans la croissance du riz et sa compétition avec les plantes adventices. En 1997, la densité moyenne initiale des œufs était de 63% supérieure à celle de 1996, tandis que la récolte moyenne était inférieure de 57% à celle de 1996. En 1997, la sécheresse a exacerbé les pertes de récolte. En 1996 et 1997, la hauteur des pieds, le nombre de chaumes et le contenu relatif des feuilles en chlorophylle étaient significativement plus faibles dans les parcelles où la densité moyenne des œufs au moment du semis était la plus élevée.

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