Association of Characters for Higher Tuber Yield of Potato (Solanum tuberosum L.) Genotypes Grown in Eastern Plains of Nepal

An experiment was conducted to study characters associated with higher yield potential of potato genotypes at the Directorate of Agricultural Research, Tarahara, Nepal during two consecutive winter seasons of 2018 and 2019. A total of eleven potato genotypes (CIP 394600.52, CIP 396012.266, CIP 393371.159, PRP 266265.15, CIP 395443.103, CIP 393371.164, PRP 336769.1, PRP 136368.9, PRP 25861.11, CIP 377957.5 and PRP 225861.5) were evaluated in a Randomized Complete Block Design with four replications. Each treatment received a 7.2 m2 plot area with 60 cm row to row and 25 cm plant to plant spacing, accommodating 48 plants per plot. Cultural practices were done as per the recommendations and fungicide was not applied for late blight of potato (Phytophthora infestans) control. The observed data were subjected to variance, correlation and cluster analysis. Analysis of variance showed significant differences for some plant and tuber characteristics. From the pooled analysis of two years’ data, the genotype 'PRP 266265.15' was found to be a suitable genotype in plains due to its higher yield (21.91 t/ha) and other yield characteristics. The higher quantity of over seed-size and under seed-size tuber contributed to the highest tuber yield of PRP 266265.15. The weight (r = 0.928**) and number (r = 0.483**) of the over seed-size tuber had a positive significant correlation with tuber yield per hectare. Further research is needed to study yield stability of the genotype 'PRP 266265.15' in various locations with similar production environments.

Agro-techniques for Production of Seed Size Tubers in Conventional Seed Potato Production System–A Review

The seed potato cost is very important component in total potato production and account for 30 to 70% which varies depending on the country or region. Tuber size is an important factor to decide the seed requirement per unit area. Seed size affects total yield, graded or marketable tuber yields. Standard seed tuber of 25–125 g weight (30–55 mm) is known as seed size tubers in India. Obtaining seed size tuber is important for achieving higher potential of the cultivars. The tuber size profile can be reduced or expanded by altering inter and intra row seed spacing, controlling days of growth by planting late or killing vines/haulm early, regulating inputs like fertilizer and water etc. An ideal combination of plant population, row width, and in-row seed spacing for a particular variety were the major factors for optimizing tuber size. Variation in tuber bulking ability in different genotypes results in variation in proportion of seed size tubers among different varieties. 70–80 days haulm killing found most suitable for getting higher proportion of seed size tubers in high bulking varieties. Proper management of N, P and K fertilizers is considered very important to maximize tuber yield and attain desirable quality. Variability in nitrogen dose/ha was observed which ranged from 100–150 between different regions of the world. Hence proper combination of above Agro-techniques should be adopted in seed production programme as per the region for getting higher proportion of seed size/plantable seed tubers.

Impacts of Elevated Ozone and Ozone protectanton Plant Growth, Nutrients, Biochemical and Yield properties of Turnip (Brassica rapa)

An experiment was conducted at woodhouse farm, Horticultural Research Station, Ooty, in the period of October 2017 to March 2018, to quantify the impact of elevated ozone and ozone protectants spray on plant growth, nutrients, biochemical and yield properties of turnip crop in a factorial completely randomized block design replicated thrice. The elevated ozone exposure significantly reduces the plant height, tuber size, tuber weight, Chlorophyll ‘a’, Chlorophyll ‘b’, Total chlorophyll, total nitrogen, total potassium, total Manganese, Iron, Zinc, Copper inturnip. Meanwhile, the elevated ozone exposure significantly increased the total phosphorous, catalase and peroxide activity inturnip. However, ozone protectants played a major role to nullify the tropospheric ozoneeffect on growth, physiology, development and yield of turnip and among them panchagavya performed well followed by neem oil and ascorbicacid.

Screening and Evaluation of Initial Clonal Generations of Potato Hybrids for Yield and Yield Attributing Characters

A field experiment was conducted during Rabi 2015-16 and 2016-17 at ICAR-Central Potato Research Station, Patna Bihar. In this experiment F1 with initial clonal generations viz F1C1, F1C2 and F1C3 were evaluated. The screening and selection of these generations were done in randomized block design for the character like early bulking, tuber size, tuber shape, depth of eye, tuber colour and resistance to late blight of potato etc. A total of 12,360 True Potato Seeds of 17 successful crosses and 7,322 True Potato Seeds of 23 successful crosses were sown and seedlings were transplanted, out of these 610 and 187 clones were selected during 2015-16 and 2016-17 respectively. Large number of potato cultures were planted for further evaluation in next generations. In F1C3 the cultures were planted along with more than six check varieties of potato. Cultures were evaluated and selected considering total tuber yield, shape, colour and disease reactions for further evaluation in PYT.

EFFECT OF TUBER SIZE AND NUTRIENT SOURCE ON THE YIELD OF YAM (DIOSCOREA SP.)

A field experiment was conducted at a private forest at Kalyanpur, Chitwan from March to January of 2018/2019 to evaluate the effect of different tuber size and nutrient source on the yield of yam (Dioscorea spp.). The experiment was laid out in a factorial Randomized Complete Block Design (factorial RCBD) with two factors i.e. tuber size viz small tuber size (<50 gm.) and large tuber size (100-150 gm.) and nutrient source viz farm yard manure, chicken manure and forest soil, replicated four times. The use of large size tubers has a significant effect on the yield of yam, higher yield (3.05 kg.) with large tuber size. Similarly, the interaction between tuber size and nutrient source was also significant on the yield. The highest yield (3.23 kg.) was made from the large size tuber (T1) and farm yard manure (M1) followed by the large size tuber (T1) and chicken manure (M2). The smallest yield (2.25 kg.) was from the interaction of small tuber size (T2) and farm yard manure (M2). Therefore, the use of a large size tuber (100-150 gm.) with farm yard manure as the nutrient source can be recommended to increase the yield of yam.

Response of potato clones to planting dates in Pokhara, Kaski, Nepal

A field trial was conducted to optimize the planting date and appropriate clone for ware potato production at Horticulture Research Station, Malepatan, Pokhara from October 2015 to March 2016. The trial was laid out in two factors Factorial Randomized Complete Block Design. There were nine treatments with three replications. The treatments comprised of three dates of planting (30th October, 14th and 29th November) and three potato clones (Janakdev, Lbr 40 and PRP 266264.1). The results showed that the main effects of planting dates and potato clones significantly (P<0.05) affected most growth, yield and yield attributing parameters of the crop. Interaction effect of planting dates and potato clones also significantly influenced the number of above-ground stems per plant, ground cover percentage, number of tubers per plant, number and weight of small size tuber (<25 g), weight of medium or seed size (25-50 g) tuber and large size (>50 g) tuber, number and yield of tubers per plot, and yield t/ha. The highest yield (37.05 t/ha) was obtained from 14th November planting. The clone Lbr 40 produced a higher yield (36.05t/ha). The clone PRP 266264.1 planting on 30th October planting produced significantly a higher yield (41.34t/ha). The clone Lbr 40 produced significantly highest number and weight of large size (>50 g) tuber. Number of small size (<25 g) tuber per plot or unmarketable tuber significantly increased on delayed planting.

Integration of different sources of organic manure and micro-nutrients on growth, yield and quality of potato (Solanumtuberosum L.) grown under new alluvial soil condition

Field experiment was conducted during rabi season of 2009-10 and 2010-11, to study the effect of application of different sources organic manure and micro-nutrients on growth, productivity and quality of potato (Solanumtuberosum L.) grown under alluvial soil. The different sources of organic and micronutrients were integrated into 8 possible treatments viz. RDF (NPK @ 200 :150 :150 kg ha-1) , 50% of RDF + well decomposed FYM @ 10t ha-1, 50% of RDF + Well powder neemcake @ 0.5t ha-1,RDF+ Zinc sulphate @ 20kg ha-1as soil application, RDF + ammonium molybdate @ 1kg ha-1as soil application, RDF + sodium tetraborate @ 1kg ha-1as soil application, RDF + tuber soaking with 40g inc sulphate + 10g ammonium molybdate + 10g sodium tetraborate, RDF + foliar spray of 1% KnO3 salt. All the treatments resulted in improvement of growth and tuber yield characteristics, out of these treatments where organic sources of nutrient were integrated registered significantly maximum effect. Highest leaf area index, leaf area duration, dry matter production, tuber bulking rate and tuber yield in potato were recorded in the treatment 50% recommended dose of NPK + 10t FYM ha-1, while the lowest was observed in 100 % inorganic fertilizer treatment (RDF). Organic treatment were also in favour of producing medium and large size tuber, whereas, micronutrient were in favour of producing extra large size tuber. Highest value of starch and reducing sugar content were also recorded under the treatment where the crop received organic manure.

Evolutionof Fertilizer Potential of Sea Weed (Kappaphycus and Gracilaria) Saps inPotato Crop inNorth Eastern Hill Region of India

A field experiment was conducted during the summer season of 2013 at Central Potato Research Station, Shillong, Meghalayato study the effect of sea weed saps on growth and productivity of potato in the North Eastern hill region of India.The trial was laid out in randomized block design, replicated thrice, with 10 treatments. The number of shoot per plant was found to be non-significant and vary from 2.8 to 3.0. The maximum plant at harvest was recorded under application 7.5 Kappaphycus Spray + 100% RDF while lowest under 6.25% + 50% RDF.Maximum small size tuber was found with an application of 10 % Gracilaria spray + RDF which was at par with 2.5 % Kappaphycus spray + RDF and 7.5 % Gracilariaspray + RDF but significantly superior to other treatment. However, the highest medium size tube of potato was noticed under 6.25% Kappaphycus spray along with 50% recommended dose of fertilizer. Highest large size tuber was recorded with an application of 5% Kappaphycusspray + RDF followed by 2.5% Kappaphycus spray along with RDF as well as 7.5 % Gracilaria spray + RDF which was at par, but significantly superior to rest of treatment. Application of 2.5% Kappaphycus spray + 100% RDF recorded the highest productivity of potato (27.1 t/ha) followedby 100% RDF + Kappaphycus spray @ 5.0% (26.6 t/ha) which were at par with each other but significantly superior to the rest of treatments.Based on the economic yield of potato, it may be concluded that the application of 2.5 % Kappaphycus spray + 100% RDF was found to be more profitable under rainfed condition of Meghalaya

Maximization of Seed Size Tubers in Potato through Manipulation of Intra Row Spacing, Nitrogen Levels and Crop Duration under Irrigated Condition in Indo –Gangetic Plains of Bihar

A field experiment was conducted during winter season (Oct-Feb) of 2013-14 and 2014-15 with four replications and eight treatments to produce maximum yield of seed size tubers of potato cultivar, “Kufri Pukhraj” by interaction of two nitrogen levels (120 and 150 kg N/ha), two intra row spacing (15 and 20cm), and two crop duration(haulm cutting at 70 and 80 days after planting). The narrow intra row spacing i.e. 15 cm, produced significantly higher yield of seed size grade tubers while wide spacing i.e. 20 cm produced higher yield of large grade tubers. The total tuber yield and tuber number was significantly more in closer spacing. Percent production of seed size tubers to total tubers (both on weight as well as number basis) was higher at narrow spacing. Haulm cutting at 80 days after planting produced significantly higher yield of large grade tuber, while haulm cutting at 70 days after planting, produced significantly higher yield of seed size grades tubers. The total tuber number and tuber yield was significantly higher in haulm cutting at 80 days after planting. Lowest total tuber yield and number was observed in wider spacing with lower nitrogen level and shorter duration. Per cent production (both on weight as well as number basis) of seed size tubers to the total tuber was significantly higher at 60 x 15 cm with 120 kg N /ha and longer crop duration. Plant spacing of 60 x 15 cm with higher fertility levels and shorter crop duration (70 day) was found to be second best treatment in terms of production of seed size tuber.