ABSTRACT
In the present investigation, phenotypic evaluation of blast disease reaction was conducted at Ponnampet and Mandya districts of Karnataka, India, which indicated that the rice varieties such as IR64, Jaya, KMP153, IR30864, Mandya Sona-1, Mandya Sona-2, KCP1, Dodda Byra, and Malgudi Sanna were susceptible to both leaf and neck blasts. Further, the rice varieties that were resistant to leaf blast such as KMP200, DHMAS70Q164-1b, Karibatta, Coimbatore Sanna and others showed susceptible reaction to neck blast only. In contrast, the varieties such as JyothixBR2655, Punkutt Kodi, Sirsi, 222 and Gangadale which were resistant to neck blast were found to be susceptible to leaf blast also. Only one variety, BR2655 showed resistance to both leaf and neck blast diseases. The genotypic studies using simple sequence repeat markers showed that the analysis of the distribution of resistance genes and genotyping of the selected rice varieties, and traditional rice varieties from different ecological regions with allele specific markers helped to identify 20 major blast resistance genes. The individual gene frequencies of the 20 major rice blast resistance genes varied from 10.34 to 100%. Less and more frequency of resistance gene distribution occurred in Pi9 and Pizt gene, respectively. The result of this study would help to create strategies for improving rice blast resistance through genetic studies and plant–pathogen interaction.
ABSTRACT
A considerable progress in plant breeding for higher yield is attained mainly through selection of morpho-physiological attributes in rice. The field experiments were conducted at three different locations under sub-tropical conditions with four early maturing rice varieties viz., Binadhan-7, Binadhan-17, BRRI dhan33, and BRRI dhan39 during kharif-2 rice season (Aman; July-October) of 2016 to find out the natural variation in the morpho-physiological attributes contributing to higher grain yield in rice. Morphological parameters on plant height, root structure, tillering ontogeny, internode elongation pattern, flag leaf length, flag leaf width, flag leaf angle, number of primary & secondary rachis, branches and also physiological traits on chlorophyll content, photosynthesis rate, total dry mass, growth rate, number of vascular bundles, harvest index with yield and yield contributing characters were studied. Results indicated that plants having rapid growth and development at early growth stages showed higher chlorophyll content, photosynthesis rate, long flag leaf, number of vascular bundles in 1st internode and also exhibited the increase in the number of grains per panicle resulting higher grain yield. Among the test varieties, Binadhan-17 showed superiority in the most morpho-physiological criteria and higher number of vascular bundles manifesting in higher grain yield. This information may help breeders to identity and develop high yielding rice variety.
ABSTRACT
ABSTRACT The upland rice farmers in Suriname use local varieties and low level technologies in the field. As a result, the upland rice grain yield is low, at about 1 000 kg ha-1. Our objective was to evaluate the use of upland rice cultivars from Suriname and Brazil, and the effect of nitrogen, N, phosphorus, P, and potassium, K, fertilizers on cultivation variables. We undertook four field trials in the Victoria Area, in the Brokopondo District, using a randomized block design each with four replications. The most productive rice varieties were BRS Esmeralda (grain yield 2 903 kg ha-1) and BRS Sertaneja (2 802 kg ha-1). The highest grain yield of 2 620 kg ha-1 was achieved with a top dressing application of 76.41 kg N ha-1 20 days after sowing. For P, the highest grain yield of 3 085 kg ha-1 was achieved with application of 98.06 kg ha-1 P2O5 applied at sowing. An application rate of 31.45 kg ha-1 of K2O at sowing achieved the highest grain yield of 2 952 kg ha-1. Together, these application rates of N, P and K resulted in rice grain yield of about 3 000 kg ha-1, which is three times greater than the national average for upland rice. We demonstrate that the use of improved rice varieties matched to the local conditions, and application of appropriate fertilizers, are management practices that can result in significant increases in rice grain yield in Suriname.
RESUMO Produtores de arroz de terras altas no Suriname usam cultivares locais e baixo nível tecnológico. Assim, a produtividade é baixa (1 000 kg ha-1). Nosso objetivo foi avaliar o uso de cultivares de arroz de terras altas do Suriname e do Brasil, e o efeito de taxas de nitrogênio, N, fósforo, P e potássio, K sobre variáveis de cultivo. Foram instalados quatro ensaios de campo usando em cada experimento o delineamento de blocos casualizados com quatro repetições. As mais produtivas cultivares de arroz foram BRS Esmeralda (produtividade de 2 903 kg ha-1) e a BRS Sertaneja (2 802 kg ha-1). A mais alta produtividade de grãos de 2 620 kg ha-1 foi alcançada pela aplicação em cobertura de 76.41 kg N ha-1, aos 20 dias após a semeadura. Para P, a mais alta produtividade de grãos de 2 620 kg ha-1 foi alcançada com a aplicação de 98.06 kg ha-1 de P2O5 na semeadura. Uma aplicação da dose de 31.45 kg ha-1 K2O na semeadura permitiu o maior rendimento de grãos, 2 952 kg ha-1. Juntas, essas taxas de aplicação proporcionaram rendimento de grãos de arroz em torno de 3 000 kg ha-1, o que é três vezes maior que a média nacional do país para arroz de terras altas. O uso de variedades melhoradas de arroz adaptadas às condições locais, e a aplicação de doses adequadas de nutrientes são práticas de manejo que podem resultar em significativo aumento no rendimento de cultivos de arroz de terras altas no Suriname.
Subject(s)
Phosphorus , Potassium , Nitrogen CycleABSTRACT
Crop related information is provided to the farmers by Government bodies and Private organisations.Farmers use this information to make farming profitable by selecting suitable varieties for that region.The information is not common to every farming station. Data mining techniques applied for provided crop research data customises it to each farming station. Present studies has been carried out on application of data mining in selection of suitable rice variety to Warangal region by obtaining the data of 20 years. Theeight rice varieties recommended by rice research station, focussing on six traits were considered for the present study. Results show that Ramappa, JGL 384, Swarna, Samba masuri are high yielding varieties in Warangal region. Kavya, MTU 1010 andWGL14 have high harvested grain weight whereas Sureka, Samba Masuri and Ramappa have least. Kavya and WGL14 showed high straw strength, panicle length and carbohydrate content. This analysis helps the farmer to select particular combination of traits to identify high performing varieties for specific location.