Yield response of selected irrigated rice varieties to varying N, P and K fertilizer regimes

Rice production has been inconsistent in Mwea irrigation scheme due to poor crop management practices and reduced soil fertility. Proper rice nutrition conserves the environment, increases sustained crop production, farmer’s crop yield and profits. A field experiment was conducted at MIAD Center, in Kirinyaga County, during 2016-17 and 2017- 18 to determine the response of rice varieties to different N, P and K fertilizer treatments. The trial was conducted in randomized complete block design, with three replications of 13 N, P and K fertilizer regimes as the main plots treatments and varieties Basmati 370 and BW 196 as the sub-plot treatment. The N kg ha-1: P2O5 kg ha-1: K2O kg ha-1 fertilizer treatment ratios used were: 00:00:00, 60:40:40, 80:60:60, 100:80:80, 60:40:00, 80:60:00, 100:80:00, 60:00:40, 80:00:60, 100:00:80, 00:40:40, 00:60:60 and 00:80:80. Plant height, number of tillers hill-1, panicle length, and grain yield responded positively to fertilizer application, but 1000-grain weight did not. Variety BW 196 recording shorter plants and panicles, more tillers hill-1, higher grain weight and yield than variety Basmati 370. 00:40:40, 00:60:60, 00:80:80, 60:40:00 and the no-fertilizer control treatments recorded the least number of tillers hill-1. 60:40:40, 80:60:60, 100:80:80, fertilizer treatments had longer panicles than the no fertilizer control and 00:40:40. Except for 100:80:00 and 00:40:40, in the first season and 60:40:00, 80:60:00, 100:80:00 in the second season, all the fertilizer regimes increased grain yield relative to the control. The highest grain yield was realized in fertilizer regime 80:60:60, 100:80:80, 80:00:60 and 100:00:80. 80:00:60 is the recommended fertilizer regime. Int. J. Agril. Res. Innov. & Tech. 8 (2): 42-46, December, 201

First Report of Rice yellow mottle virus in rice in Malawi

International audienceFirst report of Rice yellow mottle virus in rice in Malaw

YIELD RESPONSE OF SELECTED IRRIGATED RICE VARIETIES TO VARYING N, P AND K FERTILIZER REGIMES

Rice production has been inconsistent in Mwea irrigation scheme due to poor crop management practices and reduced soil fertility. Proper rice nutrition conserves the environment, increases sustained crop production, farmer’s crop yield and profits. A field experiment was conducted at MIAD Center, in Kirinyaga County, during 2016-17 and 2017- 18 to determine the response of rice varieties to different N, P and K fertilizer treatments. The trial was conducted in randomized complete block design, with three replications of 13 N, P and K fertilizer regimes as the main plots treatments and varieties Basmati 370 and BW 196 as the sub-plot treatment. The N kg ha-1: P2O5 kg ha-1: K2O kg ha-1 fertilizer treatment ratios used were: 00:00:00, 60:40:40, 80:60:60, 100:80:80, 60:40:00, 80:60:00, 100:80:00, 60:00:40, 80:00:60, 100:00:80, 00:40:40, 00:60:60 and 00:80:80. Plant height, number of tillers hill-1 , panicle length, and grain yield responded positively to fertilizer application, but 1000-grain weight did not. Variety BW 196 recording shorter plants and panicles, more tillers hill-1 , higher grain weight and yield than variety Basmati 370. 00:40:40, 00:60:60, 00:80:80, 60:40:00 and the no-fertilizer control treatments recorded the least number of tillers hill-1 . 60:40:40, 80:60:60, 100:80:80, fertilizer treatments had longer panicles than the no fertilizer control and 00:40:40. Except for 100:80:00 and 00:40:40, in the first season and 60:40:00, 80:60:00, 100:80:00 in the second season, all the fertilizer regimes increased grain yield relative to the control. The highest grain yield was realized in fertilizer regime 80:60:60, 100:80:80, 80:00:60 and 100:00:80. 80:00:60 is the recommended fertilizer regime

Foliar diseases and the associated fungi in rice cultivated in Kenya

We conducted a survey to assess the occurrence and severity of rice blast and brown spot diseases on popular cultivars grown in the Busia, Kirinyaga, and Kisumu counties of Kenya in 2019. Working with agricultural extension workers within rice production areas, we interviewed farmers (n = 89) regarding their preferred cultivars and their awareness of blast disease, as this was the major focus of our research. We scored the symptoms of blast and brown spot and assessed the lodging, plant height, and maturity of the crops (days after planting). Furthermore, we collected leaf and neck tissues for the assessment of the prevailing fungal populations. We used specific DNA primers to screen for the prevalence of the causal pathogens of blast, Magnaporthe oryzae, and brown spot, Cochliobolus miyabeanus, on asymptomatic and symptomatic leaf samples. We also conducted fungal isolations and PCR-sequencing to identify the fungal species in these tissues. Busia and Kisumu had a higher diversity of cultivars compared to Kirinyaga. The aromatic Pishori (NIBAM 11) was preferred and widely grown for commercial purposes in Kirinyaga, where 86% of Kenyan rice is produced. NIBAM108 (IR2793-80-1) and BW196 (NIBAM 109) were moderately resistant to blast, while NIBAM110 (ITA310) and Vietnam were susceptible. All the cultivars were susceptible to brown spot except for KEH10005 (Arize Tej Gold), a commercial hybrid cultivar. We also identified diverse pathogenic and non-pathogenic fungi, with a high incidence of Nigrospora oryzae, in the rice fields of Kirinyaga. There was a marginal correlation between disease severity/incidence and the occurrence of causal pathogens. This study provides evidence of the need to strengthen pathogen surveillance through retraining agricultural extension agents and to breed for blast and brown spot resistance in popular rice cultivars in Kenya