Responses of Upland NERICA Rice to Nitrogen and Phosphorus in Forest Agroecosystems

Abstract

Rice A gronomy J our n al • Volume 10 0 , I s sue 3 • 2 0 0 8 735 ABSTRACT New Rice for Africa (NERICA) cultivars are widely adopted interspecifi c crosses between Oryza sativa and O. glaberrima but their responses to fertilizer was not known. In 2004 and 2005, four released NERICAs (NERICA 1, 2, 3, 6) under two levels of phosphorus (0 and 2.6 g m -2 ) and four of nitrogen (0, 3, 6, and 12 g m -2 ) were evaluated on an acid Typic Haplustult at Ikenne (6°54´ N, 3°42´ E) in the Nigerian forest agroecosystem. In 2004, averaged over N levels, NERICA 3 attained physiological maturity most quickly (92 days aft er seeding [DAS]) at 2.6 g P m -2 . But under drought stress (2005), although NERICA 3 was the fi rst to initiate panicles (49 DAS) and to reach midfl owering (73 DAS), maturity was delayed until 100 to 101 DAS with or without P. Also, in 2005, NERICA 6 took a much longer time to mature ( 110-111 DAS) than the other cultivars. Th erefore, NERICAs 3 and 6 were the least suitable cultivars for low-input, drought-prone environments. At low N of 3 g m -2 and zero P, paddy yield was highest in NERICA 1. With application of 12 g N m -2 , NERICA 1 also yielded 20 to 41% more than the others, implying that it had a potential for tolerance to low N and was the most N-responsive among the cultivars evaluated under limited P. Moderate levels of N (6 g m -2 ) and P (2.6 g m -2 ) are recommended for NERICAs in smallholder low-input production systems.

Sensitive parameters for EPIC model evaluation and validity under soil water and nutrients limited conditions with NERICA cropping in West Africa

“…For the experiments in site 1 through 4 experimental layouts and number of replications are described and published in previous works (Oikeh et al, 2008;Saito and Futakuchi, 2009;Sokei et al, 2010;Koné et al, 2008). For 5 to 8 sites, the experimental design varies according to the area.…”

“…Indeed some traits of upland rice (japonica type) related to less adventious roots per hill result in relatively week ability in N uptake (Zhang, 2008). In addition, a severe drought that occurred just after the application of the first split of N could have induced urea volatilization resulting from the lack of N dissolution Oikeh et al (2008).…”

“…The adopted upland rice is NERICA cultivars that have been showed relatively high yieldsyield which vary in a controlled environment from 4.0 to 7.0 Mgha -1 (Akintayo et al, 2008). NERICAs are developed from interspecific crosses and tested for their ability to overcome drought (Asch et al, 2005) or to tolerate temporary inundation via flash flooding (Kawano et al, 2009) or for low nitrogen environment (Saito and Futakuchi, 2009;Oikeh et al, 2008). New cultivars including NERICA 1 and NERICA 4 are assessed through the participatory varietal selection (PVS) in order to identify genotypes that perform well across or within a specific target environment.…”

Identification of QTLs for Agronomic Characteristics in An Upland New Rice for Africa (NERICA) Variety

“…According to the Africa Rice Center (2008), NERICA varieties have high yield potential and a short growth cycle; these varieties also have resistance to local stressors such as rice blast disease and stem borers. Moreover, some NERICA varieties have biotic and abiotic stress tolerance (Cissoko et al 2011, Kang et al 2012, Oikeh et al 2008. Despite these advantages, there is still limited knowledge about the genetic basis of such important traits.…”

Bush Fallow and Cowpea Crop Use as Precedent and Organic Sources of Nutrients for Rice Cultivation on Acidic Plinthosol of Central Benin in West Africa

“…In West Africa, because of land-use intensification and limited use of nutrient inputs, the fragile upland rice production systems contributing to a third of the total rice production, are experiencing intense soil degradation, nutrient depletion and low rice productivity [6]. Thus, rice yields in the upland production systems are seldom above 1 t ha -1 despite the reported potential yield of up to 4 t ha -1 [20]. A number of solutions have been proposed to address this declining of productivity.…”