Determining Specific Window Period for Common Scab Disease Infection in Potato Tubers

A series of experiments was conducted under glasshouse and hydroponic conditions to determine the specific window period for common scab disease infection in potato tubers. The study was performed in a glasshouse system where separate tubers from the root zone were inoculated at different intervals during plant growth along with a novel hydroponic system to inoculate individual tubers at specific times of development growth allowing non-destructive observations of common scab symptoms developing. The window of tuber susceptibility to common scab disease infection was shown to vary with the season or conditions under which the plants were grown. Different internodes on tubers were found susceptible to infection at different times during tuber development. Basal internodes, which are the first sections of the tuber to expand, were susceptible to infection in the beginning of tuber development, whereas apical internodes only became susceptible later in tuber growth when the basal internodes were no longer susceptible.Journal of Nepal Agricultural Research Council Vol.3 2017: 19-2

Yield Evaluation of Nutrient-rich Potato Clones in High Hill of Nepal

A study was conducted to evaluate the yield of nutrient-rich potato clones in high-hill districts: Dolakha and Jumla of Nepal during the years 2013 and 2014, respectively. Fourteen potato clones were tested as on-station and on-farm experiments at both districts, and those fourteen clones were compared to ‘Lady Rosita' and ‘Jumli Local' respectively as the check varieties in the first year experiment, 2013. Eight promising clones were selected from the first year experiment, and were evaluated and compared with same local varieties in the consecutive year, 2014. Two clones namely; CIP 395112.32 (19.3 tha-1) and CIP 393073.179 (17.8 tha-1) exhibited superior marketable tuber yield than that of ‘Lady Rosita'(14.2 tha-1) in Dolakha and five CIP clones namely; 395112.32 (25.5 tha-1), 393073.179 (22.5 tha-1), 394611.112 (20.9 tha-1), 390478.9 (19.9 tha-1) and 395017.229 (17.0 tha-1) showed higher marketable tuber yield than ‘Jumli Local'(14.5 tha-1). Based on two years' phenotypic and tuber yield result, clones CIP 395112.32 and CIP 393073.179 are recommended to potato growers at high hills of Nepal for commercial cultivation.Journal of Nepal Agricultural Research Council Vol.3 2017: 6-1

Infection of potato tubers with the common scab pathogen Streptomyces scabiei in a soil-less system

A novel soil-less method was developed to define susceptibility of developing potato tubers accurately to infection with Streptomyces scabiei the causal agent of common scab disease. Hydroponic production enabled precise identification of individual tuber development. Direct inoculation of tubers with a spore suspension of S. scabiei resulted in disease development, demonstrating that infection could be initiated in a soil-less media. Tubers were most susceptible to infection between 3 and 20 days after tuber initiation, confirming that this early period of tuber formation is critical to disease development

Storability and Chips Quality of Chemical Treated Potatoes under Ordinary Condition

Storage experiments were conducted under ordinary room conditions in the mid hill, Khumaltar (1350 masl ; meter above sea level) and high hills, Daman (2200 masl) of Nepal during the summer season of 2011 to find out the effect of chemical treatments and their time of applications on storability and chips qualities of potato cv. Kufri Jyoti. Chemicals treatments were; CIPC (Isopropyl N (3 chlorophenyl) carbamate), hydrogen peroxide and calcium chloride, which were applied as a single dose (before storage) and double dose (before and at 45 days in storage). Ordinary water treated potatoes served as control. The treatments were replicated thrice. Apparently healthy tubers > 60 gram weight after different chemical treatments were stored in bamboo racks and wooden tray, respectively at Kumaltar and Daman for 120 days. Observations were recorded on weight loss percentage (WLP), sprouting percentage, numbers and weight of sprouts and quality parameters for chips. Double fumigation with CIPC was effective for inhibition of sprouting and reduction of postharvest loss up to 120 days in both the locations. On the other hand the better colour of the chips was produced by two times hydrogen peroxide treated potatoes

Growth Status, Curd Yield and Crop Duration of Late Season Cauliflower Varieties

Cauliflower is an important winter season vegetable crop having year-round demand in Nepal. Due to longer crop duration in late winter season, there was a production of poor-quality curds and lower yield faced by the farmers in Terai region of Nepal. An experiment was conducted to identify the short duration late season varieties at Rampur, Chitwan Nepal during November 2016 to March, 2017. These varieties were Freedom, Titan, Ravella, Amazing, Artica, Bishop, Casper, Indam 9803 and NS 106 (introduced from USA, Europe and India), and Snow Mystique and Snowball 16 (introduced from Japan). The experiment was laid out in Randomized Complete Block Design (RCBD) with four replications. The highest plant height (71.9 cm) and canopy diameter (74.5 cm) at last harvest of cauliflower was mostly produced by Titan followed by NS 106, Snow Mystique, Bishop and Indam 9803. Similarly, significantly shorter period for final curd initiation of 65 days after transplanting was observed in Freedom and shorter period for final curd maturation of 77 days after transplanting was also recorded in Freedom than other varieties. Significantly, higher curd yield of 54.8 t/ha was produced by Bishop than other varieties. In conclusion, Bishop was the best hybrid variety while other suitable varieties were NS 106, Titan, Artica and Snow Mystique for better growth and higher curd yield in Chitwan condition. Similarly, Freedom was identified as short duration varieties which can minimize the negative effects in late winter season due to higher temperature