Morphological variation of iron toxicity tolerance in lowland rice (Oryza sativa L.) varieties

Rice (Oryza sativa L.) is a staple food crop in many countries in Africa. Africa consumes 11.6 million tons of rice per annum and out of 39 rice-producing countries, 21 import 50% to 99% of their rice requirements. The inability to reach the yield potential that would sustain Africa’s need for rice is due to many biotic and abiotic constraints that rice production faces. In lowland grown rice, one of the abiotic factors hindering rice production is iron toxicity. Excess uptake of ferrous (Fe2+) ions leads to a physiological stress, which results, into poor production. The current study aimed at selection of varieties tolerant to iron toxicity and assessment of the genetic diversity linked to this trait. In a hydroponic experiment conducted in a screen house at Africa Rice Centre in Dar es Salaam, 32 rice varieties were evaluated for tolerance to iron toxicity. The experiment was laid out in a split plot design with iron concentration as the main plot factor and variety as the sub plot factor. Two levels of iron concentration were used: 2 ppm and 300 ppm of Fe2+ as control and test concentrations, respectively. Traits observed to gauge tolerance were leaf bronzing (an indicator of iron toxicity), plant height, tillering, number of leaves, shoot weight (above ground), root length and root weight. The varieties ARICA8, and CK801 were found to be tolerant due to low bronzing indices, higher shoot weight, more number of leaves and lack of significant variation in morphology between the two Fe treatments except for the plant height. Correlation analysis depicted negative correlation between leaf bronzing and the other traits measured especially shoot biomass.

Evaluating the Presence of Pesticide Residues in Organic Rice Production in An Giang Province, Vietnam

The presence of pesticide residues was investigated in the organic rice production model in An Giang province, Vietnam. A total number of sixteen pesticide residues was been recorded during the investigation. Based on their contamination rate, they are classified as follows. The high-risk group includes tricyclazole (80%). The medium-risk group includes chlorpyrifos (47%), isoprothiolane (47%), difenoconazole (40%), propiconazole (40%), hexaconazole (40%), chlorfenapyr (33%), azoxystrobin (20%), and cypermethrin (20%). The low-risk group includes metalaxyl & metalaxyl-M, paclobutazol, niclosamide, chlorfenson, fipronil, fipronil-desulfinyl, and fenoxanil, which were detected with a contamination rate of 7%. There were seven insecticides, seven fungicides, one snail killer, and one growth regulator.

Rice Subsector Development and Farmer Efficiency in Nepal: Implications for Further Transformation and Food Security

With economic development agricultural systems in the Global South transform from subsistence farming to higher productivity with market integration and increase in rural income and food security. In Nepal, agriculture continues to provide livelihoods for two-thirds of the predominantly rural population, largely at a subsistence-level. Rice is the staple food and covers the largest land area but yields are relatively low, with an annual import bill of USD 300 Million. The study uses data from 310 households from two distinct rice producing areas to assess farmers' rice production systems. It analyses farmers' rice production efficiency using a stochastic frontier production function to suggest how to advance the transformation of Nepal's rice sector. Our study finds that while agriculture related services such as access to inputs, information, markets, irrigation, and finance have generally improved, paddy farmers are only able to achieve 76% of potential output. Small/marginal farms were relatively less efficient than medium and large farms. Women farmers faced unequal access to technologies and have lower productivity than men. Unavailability of labor and capital, land fragmentation, and the lack of consistent access to seed and fertilizers contribute to reduced efficiency. Public and private sector investments are needed to enhance the timely and adequate access to quality seeds, fertilizers, processing facilities, and equipment services. Adopting a market systems approach through cooperative farming, targeted delivery of extension services, and linkages with rice millers can promote inclusive growth and improve rice food security in Nepal.