Late blight caused by Phytophthora infestans (Mont.) de Bary is an important disease of potato and tomato that occurs annually in the hills and occasionally in the terai (plain) of Nepal. In 1996 and 1997, each year, 50 samples of late blight-infected potato and tomato leaves were collected from the hill and terai areas. The pathogen was cultured on Rye A agar. Each isolate was paired on clear V8 agar with reference isolates DN111 (A1 mating type) and DN107 (A2 mating type) received from Hokkaido University, Japan, and examined for oospore formation after 10 to 15 days of incubation at 20°C. The proportion of A2 isolates was 6% in 1996 and 42% in 1997. The A2 isolates were mainly from the high hills (2,000 to 2,500 m) where local and Andean types of potatoes are grown. Analysis of genotypes of isolates at the glucosephosphate isomerase (GPI-1), malic enzyme (ME), and peptidase (PEP-1) (1,2) isozyme loci revealed genetic diversity between A1 and A2 isolates. A1 isolates from potato were either homozygous (100/100) or heterozygous (86/100) for GPI-1, whereas all A1 isolates from tomato were heterozygous (86/100). All A1 isolates were homozygous (100/100) at the ME locus and heterozygous (92/100) at the PEP-1 locus. A2 isolates were homozygous (100/100) at all isozyme loci. The results show that both A1 and A2 mating types of P. infestans are present in Nepal, and that they display different isozyme genotypes. It is speculated that the A1 type may have migrated with potatoes from Europe while the A2 type may have been introduced with Andean potatoes from Latin America more recently. The simultaneous occurrence of both mating types may allow the fungus to increase its pathogenic diversity and to survive by means of oospores. References: (1) A. A. Mosa et al. Plant Pathol. 42:26, 1993. (2) P. W. Tooley et al. J. Hered. 76:431, 1985.
Eupatorium adenophorum Sprengel is a forest killer widely spreading as weed in Nepal. A study on its ecology and utilization was carried out in central Nepal with reference to its gall formation. This banmara is attacked by Procecidochares utilis, a gall which causes metabolic and physical damage to the plant. The main field survey was done in Gorkha-Langtang area and compared with the phenomenon with that of Kathmandu Valley. It has been found that the index of exposure has no effect on the plant growth; pH also has no effect where as soil and gall formation has some effect on plant growth. Artemisia vulgaris and Urtica dioca were commonly found in association with Eupatorium adenophorum. Though the plant acts as forest killer, some beneficial phenomena were also recorded.Key words: Correlation coefficient; Gall formation; index of exposure; life cycle; quadratesJournal of Natural History Museum Vol. 23, 2008 Page 108-124
The study was conducted to analyze the socioeconomic factors and profitability of hybrid maize production in eastern Nepal. A household survey was conducted from March to April, 2017 in two districts Morang and Sunsari to collect information on socioeconomic characteristics and economics of maize production. The Structured questionnaire was administered to 98 randomly selected households from two districts i.e. 41 from Morang and 57 from Sunsari district. Descriptive and statistical tools including multiple regression model were used to analyze the data. The multiple regression model showed that larger the maize area, higher the education of household head and households who received maize farming related training were significant and positive towards maize output. Farmers of Morang district have higher maize production than Sunsari district. The benefit-cost ratio (1.7) indicates that hybrid maize farming was profitable with productivity of 6.9 ton per hectare. Despite the importance of maize crop to household income, many constraints were reported in its productivity including lack of irrigation, a high cost of inputs and the incidence of pests and diseases. Ensuring access to irrigation, training on maize farming, mechanization and efficient extension services were recommended to increase hybrid maize production in eastern Nepal.
Wheat (Triticum aestivum L.) is one of the major staples in Nepal providing the bulk of food calories and at least 30% of Fe and Zn intake and 20% of dietary energy and protein consumption; thus, it is essential to improve its nutritional quality. To select high-yielding genotypes with elevated grain zinc and iron concentration, the sixth, seventh, eighth, and ninth HarvestPlus Yield Trials (HPYTs) were conducted across diverse locations in Nepal for four consecutive years: 2015–16, 2016–17, 2017–18, and 2018–19, using 47 biofortified and 3 non-biofortified CIMMYT-bred, bread wheat genotypes: Baj#1, Kachu#1, and WK1204 (local check). Genotypic and spatial variations were found in agro-morphological traits; grain yield and its components; and the grain zinc and iron concentration of tested genotypes. Grain zinc concentration was highest in Khumaltar and lowest in Kabre. Likewise, grain iron concentration was highest in Doti and lowest in Surkhet. Most of the biofortified genotypes were superior for grain yield and for grain zinc and iron concentration to the non-biofortified checks. Combined analyses across environments showed moderate to high heritability for both Zn (0.48–0.81) and Fe (0.46–0.79) except a low heritability for Fe observed for 7th HPYT (0.15). Grain yield was positively correlated with the number of tillers per m2, while negatively correlated with days to heading and maturity, grain iron, grain weight per spike, and thousand grain weight. The grain zinc and iron concentration were positively correlated, suggesting that the simultaneous improvement of both micronutrients is possible through wheat breeding. Extensive testing of CIMMYT derived high Zn wheat lines in Nepal led to the release of five biofortified wheat varieties in 2020 with superior yield, better disease resistance, and 30–40% increased grain Zn and adaptable to a range of wheat growing regions in the country – from the hotter lowland, or Terai, regions to the dryer mid- and high-elevation areas.
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