Rainfed Rice Farming Production Constrains and Prospects, the Kenyan Situation

Kenya experiences huge production-consumption deficit in relation to rice. This is due to changing eating habits that has adopted more rice in the menu and rapidly rising population. Rice production has remained low being unable to meet consumption. Rice ecosystems in Kenya include irrigated, rainfed lowland and rainfed upland. Irrigated ecosystem has over the years been given more emphasis despite rainfed rice farming having double the potential over irrigation system. Ecologically rice grows well in abundant water supply, warm to high temperatures and in Clay sandy to loamy soils with slightly acidic to neutral pH. Rice varieties grown in Kenya are mainly traditional, introduced improved, hybrids and landraces. Rainfed rice farming faces constraint’s key among them being; drought and erratic rainfall, weeds, pest and diseases, cheap imports, land ownership and poor infrastructure. Mitigating against drought and erratic rainfall, improving farm inputs and equipment, increasing germplasm production and distribution, credit support and marketing to farmers, improving farmers skills through technological transfers and infrastructural development are prospects that if adopted could increase rainfed rice productivity. More attention towards improvement of rainfed rice farming could greatly contribute to bridging the production-consumption deficit that is bridged through imports. It is with this, that this review updates our understanding of rain fed rice farming in Kenya in terms of ecological conditions, ecological systems, varieties, constraints and prospects.

Genetic diversity for drought and low-phosphorus tolerance in rice (Oryza sativa L.) varieties and donors adapted to rainfed drought-prone ecologies

Drought and phosphate availability are two major abiotic factors limiting productivity of rice in rainfed upland areas. There has been a constant need for new improved donor with tolerance to multiple abiotic stress conditions for rainfed rice breeding. In the present study, a set of 32 popular rice varieties and landraces were evaluated for drought and low-phosphorus (P) tolerance, and also characterized using grain yield under reproductive drought QTLs (DTY QTLs) and Pup1 linked/specific molecular markers. Twenty-seven genotypes were identified as tolerant to moderately tolerant to drought. The SSR markers linked to ten DTY QTLs classified the genotypes into two groups corresponding to aus and indica. The tolerant genotypes were distributed under both groups. Based on the core markers of Pup1 locus, complete tolerant haplotype was recorded in nine genotypes other than the tolerant check Dular. Nine more genotypes showed the incomplete tolerant haplotypes. The rice genotypes showed significantly high genetic variability for low-P tolerance in hydroponic study. A few genotypes revealed non-Pup1 type tolerance which needs further confirmation.

Effect of Plant Geometry on Different Rapeseed Varieties under Rainfed Upland Condition in Nepal

The field experiment was carried out during winter of 2018/19 with two varieties (Unnati and Surkhet-Local) and three plant geometry (15cm × 10 cm, 30cm × 10 cm, 45cm × 10cm) in Randomized complete block design (RCBD) with four replications. Statistically there was no difference between two varieties while differences were found on different spacing and interaction between variety and spacing on final seed yield. High significant differences on seed yield was due to spacing and yield of rapeseed were higher at the 30 cm inter row spacing as compared to the 15 cm and 45 cm inter row spacing. Statistically significant effect was found on mean values of seed yield for interaction which showed that Unnati cultivar in 30 cm x 10 cm plant geometry had the highest seed yield (969.86 kg/ha) followed by Surkhet-local with spacing of 15 cm × 10 cm (843.75 kg/ha) and 30 cm × 10 cm (823.76 kg/ha). Yield of these varieties decreased as spacing is increased, thus sowing of Unnati should be done at cropping geometry of 30 cm × 10 cm and for Surkhet-local it should not be done beyond 30 cm inter row spacing to get the maximum potential yield. Int. J. Appl. Sci. Biotechnol. Vol 9(2): 113-121.

Acid Soil Management in Jhum Fields of Maize under Zunheboto District of Nagaland

Maize (Zea mays L.) is an important cereal crop in the world due to its adaptability towards varied agro-climatic conditions. It is considered the Queen of the cereals. It ranks third among the cereals next to wheat and rice. The leading producer of maize is USA with 10.34 t ha -1 followed by Argentina (5.61 t ha-1) and China (5.35 t ha-1). It is the third most important cereal next to rice and wheat contributing about 10% of the total food grain production. Maize is the second most important crop next to rice in the Northeast region of India grown under rainfed upland soils. It is used for direct consumption as well as feeds to the farm animals. The area under maize in Zunheboto district of Nagaland is 10,100 hectare, however its productivity is only about 1.98 Mt ha-1 and hence its production needs to be improved. The soils are acidic in this region and often needs to be reclaimed to increase the productivity of the maize. A field level demonstrations on acid soil management using lime was conducted based on the soil type and pH in upland jhum fields of Aotsakili and Sumi Settsu villages under Zunheboto district of Nagaland covering 2 hectares. It was observed that with the application of lime, the average mean of pH was increased from 6.2 to 6.4 and the mean yield of maize was 2300 kg ha-1 over control (1600 kg ha-1) with B:C ratio of 2.6 over farmers practice 2.2. This technology was found to be beneficial and suitable for neutralizing soil acidity for crop production.

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

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

Farmers’ Preferred Traits and Perceptions of Drought Stress on Rainfed Upland Rice Production across Two Rice Growing States of Nigeria

The intermittent and widespread occurrence of drought in rainfed upland rice fields across sub-Sahara Africa has led to tremendous decrease in food security in the region. Although high yielding, drought tolerant varieties have been developed over years to mitigate this trend, limited adoption had been recorded for most of these materials. This study investigated farmers’ perceptions on drought stress and their preferred traits in new upland rice varieties across two major upland rice growing states in Nigeria. Participatory Rural Appraisal was conducted among 119 rice farmers using comparative approach, probing and semi structured interviews. Result based on farmers knowledge of changes in rainfall pattern and preferred traits such as plant architecture and grain shapes in a new upland rice variety differed significantly across the two state. The results identified drought stress as one of the main constraints to upland rice production across communities. The ideal upland rice variety desired by most respondents in both states should be of medium plant height (115-130cm) characterized by white, long and bold grains. This study has demonstrated the importance of understanding farmer’s desired traits in a new upland rice variety and the need to incorporate identified traits in creation of resilient new upland rice varieties adaptable to rain-fed upland rice growing regions of Nigeria.

Ephemeral Growth span and Rapid Veg-repo shift is Critical for Survival against Naturally Rainfed Upland and Erratic Drought in Rice Growing Regions

Two experiments were undertaken simultaneously (early generation evalua-tion and advanced generation evaluation respectively) during Kharif 2013-14 at S G College of Agriculture and Research Station, Jagdalpur, IGKV, Raipur, Chhattisgarh, to indentify and analyze ephemeral genotypes for their suitability in rainfed upland and present era’s climate change-laid unpredicted water stress production agro-ecosystem. In early generation testing, mean plot flowering was recorded to be 72 Days After Sowing (DAS), plant height 83cm, panicles per square meter 212 and grain yield to be 2330kg/ha. Regional check Vandana and CRR-676-1 flowered earliest by 68 DAS followed by CRR-627-35-1-5 (69 DAS) and CRR-507-11-B-1 and CRR-605-23-1. The CRR-433-2-1-1 flowered latest by 83 DAS and as per hypothesis; yield was con-siderably reduced since plant could not develop optimum source-sink bal-ance and carbon accumulation in seeds eventually. Regarding, crop yield, five genotypes placed above the local check, namely CRR-597-5-1 (29.47%), the national check i.e. Anjali (21.05%), CRR-676-1 (15.79%), CRR-433-2-1-1 (10.53%) and the regional check i.e. Vandana (7.92%). Among advanced ma-terial, interestingly, the highest yielding genotype flowered earliest (69 DAS) that suggests the accomplishment of crop growth and physio-biochemical development while utilizing the soil and environmental reserve appropriate-ly. On overall, mean yield was 2349kg/ha, whereas genotype CRR-616-B-2-54-1 ranked 1st with 2718 kg/ha yield, 69 days of flowering duration and short bold grains. The bimodal experiment concludes that ephemeral growth span and rapid veg-repo shift is critical for survival against naturally rainfed-upland and erratic drought in rice growing regions and those genotypes which maintain the physiological buffer at the shift will be able to sustain genetic yield potential.