Plant characteristics associated with weed competitiveness of rice under upland and lowland conditions in West Africa

Weeds are a major constraint to rice (Oryza spp.) production in West Africa. Superior weed competitive rice genotypes may reduce weed pressure and improve rice productivity. Two upland and two lowland experiments were conducted in southern Benin to examine genotypic variations in weed-suppressive ability and grain yield under weedy conditions, and to identify plant characteristics that could be used as selection criteria for improved weed competitiveness. A total of 19 genotypes, including Oryza sativa and Oryza glaberrima genotypes and interspecific hybrids developed from crossing O. sativa and O. glaberrima, were grown under weed-free and weedy conditions in an upland with supplemental irrigation and in a flooded lowland. In weedy plots, hand weeding was done once or not at all. Mean relative yield loss across all genotypes due to weed competition ranged from almost 0% to 61%. Large genotypic variations in weed biomass and grain yield under weedy conditions were found. Visual growth vigor at 42 and 63 days after sowing (DAS) under weed-free conditions significantly correlated with weed biomass at maturity in both upland and lowland experiments (R2 = 0.26–0.48). Where weed pressure was low to moderate, with mean relative yield loss less than 23%, the multiple regression models using grain yield and plant height at maturity or only grain yield measured under weed-free conditions as independent variables could explain 66–88% of the genotypic variation in grain yield under weedy conditions. At higher weed pressure (mean relative yield loss: 61%), as observed in one of the upland experiments, biomass accumulation of rice at 42 days after sowing was associated with higher grain yield under weedy conditions. Biomass accumulation also significantly correlated with visual growth vigor at the same sampling dates. Therefore, we conclude that grain yield, plant height at maturity and visual growth vigor at 42–63 DAS under weed-free conditions appear to be useful selection criteria for developing superior weed competitive rice genotypes

Grain Yield Performance of Selected Lowland NERICA and Modern Asian Rice Genotypes in West Africa

Six lowland experiments were conducted over three years in southern Benin to assess yield differences in 28 rice (Oryzaspp.) genotypes grown under nonfertilized and fertilized conditions. These included the interspecifi c hybrids, the lowland New Rice for Africa (NERICA) genotypes developed from crossing O. sativa and O. glaberrima. Fertilizer rates were 70–86N: 30–37P2O5: 30–37K2O kg ha–1. Fertilizer applicationincreased average grain yield across all genotypes and experiments by 39% (154 g m–2increase). Considerable genotypic differences existed in grain yields under both nonfertilized and fertilized conditions, and in yield response to fertilizer application. Two lowland NERICA genotypes (‘NERICA-L-6’ and ‘-54’) outyielded‘IR 72’ and ‘WITA4’ (standard checks) acrossnonfertilized and fertilized conditions in fourexperiments with favorable water availability inwet seasons (651 vs. 575 g m–2). The high grainyields resulted from large spikelet number m–2and biomass accumulation. In contrast, threeindicagenotypes from Asia (‘B 6144F-MR-6-0-0’, ‘IR 70181-32-PMI-1-1-5-1’, and ‘PSBRc 80’)outperformed the checks in two experiments,one straddling wet and dry seasons and theother with no standing water during most of theusual wet rice-growing season. These resultsindicate that while specifi c adaptations arelikely to provide significant yield advantage inparticular environments, interspecifi c breedingstill offers an effective approach to improvinglowland rice productivity

Genotypic adaptation of rice to lowland hydrology in West Africa

In West Africa, the lowlands comprise a wide range of hydrological environments—from permanently flooded to permanently non-flooded conditions. Rice breeding programs must develop genotypes that are expected to perform well either across all hydrological environments or for a specific target population of environments. We evaluated 14 rice (Oryzaspp.) genotypes in seven experiments during 2 years (2007 and 2008) in Benin to investigate genotype×environment (G×E) interaction for grain yield, and to identify high-yielding genotypes and plant characteristics associated with high yield. The genotypes consisted of O. sativa indicagenotypes, including ‘aerobic rice genotypes’ and interspecific genotypes, developed from crossing O. sativa and O. glaberrimafor upland (‘NERICA’ genotypes) and lowland conditions (‘NERICA-L’). The mean grain yield ranged from 231 to 588 gm−2 across experiments, with the highergrain yields from flooded lowland conditions. The G×E interaction accounted for 22% of the total sum of squares, with environment and genotype responsible for 71 and 8%, respectively. Three environment groups were identified from a pattern analysis on grain yield. Grouping was related to water availability, distinguishing (i) an aerobic environment, with rice grown under aerobic conditions with supplemental irrigation, (ii) a hydromorphic environment, with rice grown under rainfed conditions with drought spells at the vegetative stage, and (iii) a permanently flooded environment. An interspecific genotype WAB1159-4-10-15-1-3 produced high yields in both flooded and hydromorphic environments,while two interspecific genotypes, NERICA-L-6 and NERICA-L-54 performed well only in a flooded environment. An aerobic rice genotype B 6144F-MR-6-0-0 outyielded these three interspecific genotypes in the aerobic environment. High grain yields in the flooded and hydromorphic environments resulted from biomass accumulation rather than harvest index, whereas the higher yield in the aerobic environment was the result of harvest index rather than biomass accumulation. Genotypes with high growth vigor at 42 and 63 days after sowing tended to have higher yields in the flooded and aerobic environments. Grain yield in the hydromorphic environment was positively correlated with growth duration. We conclude that while interspecific breeding appears to offer an effective approach to improving lowland rice productivity, a systematic effort is needed to screen a wide range of O. sativa and interspecific genotypes across hydrology gradients in West Africa to identify genotypes that perform well across or within a specific target population of environments

Combined effects of Stylosanthesguianensisfallow and tillage management on upland rice yield, weeds and soils in southern Benin

Intensifying upland rice cultivation has resulted in increased weed pressure and declining soil fertility and rice yield in West Africa. Integrated crop management technologies are needed for enhancing rice productivity. A field experiment was conducted from 2006 to 2008 in a TypicHaplustult soil in southern Benin to identify the optimal seeding date of stylo relay-cropped into upland rice, and to evaluate the effects of fallow treatment and tillage management on rice yield, weed biomass and soil properties. Stylosanthesguianensis(stylo), a legume species, was used as a short-term fallow crop. Rice was grown once each year and stylo was seeded during the wet season and grown until the next rice-growing season. The effects of fallow treatment and tillage management (no-tillage vs. manual-tillage) on weed biomass during the rice-growing season were evaluated in 2007 and 2008, whereas the effects on rice yield were examined in 2007 alone. Results indicated that stylo can be established as a relay crop withupland rice about 10 days after rice seeding. Stylo fallow reduced weed biomass by 71% and 95% and increased total biomass (weed + stylo + litter) by 594% and 107% at the end of the dry seasons in 2007 and 2008, respectively. No-tillage without stylo fallow increased weed biomass by 62–202% over manual-tillage during the rice-growing seasons, whereas stylo fallow reduced weed biomass by 45–83% and 11–36%, respectively, under no-tillage and manual-tillage management. There were no significant effects of fallow treatment and tillagemanagement on soil organic C, total N, inorganic N and extractable P. Rice yields following stylofallowwere 0.7 Mg ha_1 higher than after the natural fallow. Manual-tillage increased rice yield by 0.6 Mg ha_1 over no-tillage. Manual-tillage combined with stylo fallow can be recommended to smallholder farmers for improving upland rice productivity

Factors affecting variation in farm yields of irrigated lowland rice in southern-central Benin

For increasing rice production in West Africa, both expansion of rice harvested area and raising rice yield are required. Development of small-scale irrigation schemes is given high priority in national rice development plans. For realizing potential of the newly developed schemes, it is essential to understand yield level, farmers’ crop management practices and production constraints. A series of field surveys were conducted in six small-scale irrigation schemes in Zou department, Benin during the dry season in 2010–2011 to assess variation in rice yields and identify factors affecting the variation. The schemes were established between 1969 and 2009. Rice yields ranged from 1.3 to 7.8 t ha−1 with an average yield of 4.8 t ha−1. The average yield was only 2.9 t ha−1 for newer irrigation schemes developed in 2002 and 2009. Multiple regression analysis using farmers’ crop management practices as well as abiotic and biotic stresses as independent variables revealed that 75% of the variation in yields could be explained by five agronomic factors (fallow residue management, ploughing method, water stress, rat damage and N application rate) and two edaphic factors (sloped surfaces and sand content in the soil). Removing fallow residue from the fields for land preparation reduced yields. Yields were lower in plots ploughed by hand than by machine. Sloped surface, water stress and rat damage reduced yields. Yield increase due to N application ranged from 0.8 to 1.6 t ha−1. Higher sand content was associated with lowered yields. The low yields in new irrigation schemes caused by sub-optimal crop management practices suggest that farmer-to-farmer learning and extension of good agricultural principles and practices can increase yields. Organizational capacity is also important to ensure the use of common resources such as irrigation water and tractors for land preparation

Mindful Parenting as a Mediator in Parents’ Perspective-Taking: Exploring the Roles of Causal Attribution and Self-Compassion

Fitri Ariyanti Abidin,1,2 Shally Novita,1,3 Kustimah Kustimah,1,3 Bewizta Maurilla Hasyyati,2 Mumtaz Azoma,2 Shadira Fianni Darmagita,2 Kinanthi Ayu Larasati,2 Athifah Qonita Millati2 1Department of Psychology, Faculty of Psychology, Universitas Padjadjaran, Sumedang, Indonesia; 2Center for Family Life and Parenting Studies, Faculty of Psychology, Universitas Padjadjaran, Sumedang, Indonesia; 3Center for Psychological Innovation and Research, Faculty of Psychology, Universitas Padjadjaran, Sumedang, IndonesiaCorrespondence: Fitri Ariyanti Abidin, Department of Psychology, Faculty of Psychology, Universitas Padjadjaran, Jln. Ir. Soekarno km. 21. Jatinangor, Kab, Sumedang, Jawa Barat, 45363, Indonesia, Tel +62 22 7794126, Fax +62 22 87920376, Email [email protected]: Existing literature has examined the link between parent causal attribution and self-compassion in parent perspective-taking, but the impact of mindful parenting as a mediator remains underexplored.Purpose: The present study examines the mediating effect of mindful parenting on the relationship between parental attribution and self-compassion in parents’ perspective-taking.Methods: Using a cross-sectional design, 208 parents aged 30 to 59 (M = 42, SD = 4.3) with first-born adolescents aged 12– 18 participated in the study.Results: The results revealed that mindful parenting fully mediated the relationship between parental causal attribution and perspective-taking while partially mediating the association between self-compassion and perspective-taking.Conclusion: These findings emphasize the crucial role of mindful parenting in explaining the relationship between parent causal attribution, self-compassion, and parent perspective-taking. Further research is needed to explore these relationships in more diverse and representative samples.Keywords: mindful parenting, parent causal attribution, parental self-compassion, parents-adolescents, perspective takin