Efficacy of Growth Regulators on Flowering of Gerbera (Gerbera jamesonii B.) cv. Goliath in Open Field Condition

Background: Application of plant bioregulators at specific concentration modify growth, flowering, flower yield and post harvest quality of flowers. Growth promoters like auxin, gibberellins and cytokinin modify physiological process by accelerating plant growth while growth retardant like cycocel and abscisic acid inhibit plant growth. But in open field cultivation of gerbera, little is known about use of growth regulators on flowering regulation. A good knowledge on use of growth regulators in gerbera is required before going to any recommendations. The current study aimed to standardize suitable bioregulators on flower production in gerbera in open field condition. Methods: The study was carried out in premises of Biotechnology cum Tissue Culture Centre, Odisha University of Agriculture and Technology, Bhubaneswar during 2015-16 and 2016-17. Apart from control eight treatments of growth regulators were used like GA3 @ 100 ppm and 150 ppm, cycocel @ 700 ppm and 800 ppm with or without amino acids as foliar spray. The observation were recorded from 5 randomly selected plant within each replication of treatment for different floral parameters. Result: The result revealed that days taken to flower bud initiation and days taken to flowering was minimum in GA3 @ 100 ppm + amino acid. The stalk length of flower was maximum in treatment GA3 @ 150 ppm + amino acid while largest flower diameter, maximum number of flowers and longest bloom life was observed in treatment with cycocel @ 700 ppm + amino acid. Maximum stalk thickness was found in treatment with cycocel @ 800 ppm + amino acid. The present work will be a complementary contribution to the researchers and gerbera growers in increasing productivity of this flower crops.

Microclimate suitability for green and coloured sweet pepper hybrids in open and protected structures in sub-tropical humid climate of West Bengal

A study was undertaken for two consecutive seasons (autumn-winter) to evaluate the performance of three green, red and yellow-fruited sweet pepper hybrids in open field and under two protected structures (50% green shade net house and naturally-ventilated polyhouse) to understand the microclimate suitability for maximizing the productivity of these hybrids under sub-tropical humid climatic condition of eastern India. In this climatic condition, naturally-ventilated polyhouse was most suitable for enhancing fruit yieldof both green and coloured fruited hybrids. Open field condition was not suitable for both yellow and redfruited hybrids. Though green-fruited hybrids could be grown in open field condition, fruit yield was more than double under polyhouse. Shade net house could not be considered as a suitable protected structure for sweet pepper in this climatic condition because of reduced light intensity and high relative humidity inside it causing low fruit set and high incidence of bacterial wilt disease. Maximum/minimum temperature30oC to 33oC / 14oC to 17oC with comparatively reduced light intensity of 35,000 to 55,000 lux, prevention of adverse effect of low night temperature during winter and  60 per cent relative humidity condition during flowering, fruit set and fruit development period inside the naturally ventilated polyhouse were most suitable growing conditions for getting maximum productivity of both green and colour-fruited hybrids of sweet pepper.

Association Mapping, Trait Variation, Interaction and Population Structure Analysis in Cucumber (Cucumis Sativus L.)

In several regions of the world, low productivity in this crop is attributed to several factors including poor understanding of the genomic complexity of important traits associated with fruit quality and yield. Therefore, genome wide association analysis was performed for important traits using simple sequence repeats (SSR) markers. Significant variation was recorded for all the studied traits in 78 cucumber genotypes under two environments (open field and net house) which indicated that the constituted association panel was suitable for association mapping. Genotyping was done using 60 highly polymorphic SSRs. By performing genome scanning out of 60 SSR markers, using mixed linear model (MLM) approach 4 and 6 markers explained an average of 23.93% and 17.37 % of the trait variation under net house and open field condition, respectively. Based on MLM approach two markers on 3rd chromosome (UW084942) and 4th chromosome (UW062953) found to be associated with the average fruit weight (g) under both net house and open field condition. Population structure analysis revealed four distinct sub-populations that corroborated with the geographical origin as well as fruit quality and quantitative traits. The four sub-populations (A–D) had fixation index percentage (Fst) equal to 24.35 29.48, 37.17 and 8.97 respectively, supporting the existence of moderate population structures. Therefore, the extensive phenotypic and genotypic characterization, population structure, and markers associated with critical traits provided in this study will facilitate marker assisted improvement programs in cucumber.

Effect of Grafting Dates on Graft-take Success and Sapling Growth of Persian Walnut (Juglans regia L.) Under Open Field Condition of Jumla, Nepal

A field experiment was carried out at Horticultural Research Station, Rajikot, Jumla to determine the best grafting date of walnut for the highest graft-take success and sapling growth. The experiment was conducted during the two consecutive years 2017, and 2018. Two varieties namely ‘Hartley’ and ‘Payne’ and four different dates of grafting viz. 15th March, 22nd March, 29th March, and 5th April were used as the treatment and the experiment was laid out in split-plot design. Each treatment was assigned with ten grafts with five replications per treatment. The measured parameters for the experiments included graft-take success (%), final scion diameter (cm), growth on scion diameter (%), number of primary branches per plant, plant spread (cm), and number of leaf per plant. The pooled value of observation for two years showed highly significant effect of variety and grafting date on grafting-take. ‘Hartley’ variety showed maximum graft-take success (73.2%) and ‘Payne’ with the least success (54.0%). The pooled value of two successive years showed the highest graft-take success (70.0%) on 15th of March, significantly at par with 22nd March (64.5%) and 29th March (67.0 %) grafting. Grafting on 15th March was also superior in terms of number of leaves (31.7), and least was observed for grafting on 29th March (20.5). In essence, variety ‘Hartley’ was found to record higher graft-take success with 15th March as the optimum grafting date under Jumla condition.

Effect of Organic and Inorganic Sources of Nutrients on Flowering of Hybrid Gerbera (Gerbera jamesonii B.) cv. Shimmer in Open Field Condition

The present investigation on Effect of organic and inorganic sources of nutrients on flowering of hybrid gerbera (Gerbera jamesonii B.) cv. Shimmer in open field condition was conducted at Biotechnology cum Tissue Culture Centre, OUAT Bhubaneswar during 2015-16 and 2016-17. The aim of the study was to find out suitable organic and inorganic sources of nutrients for cut flower production of gerbera in open field condition. There were eight treatment combinations consisting of 100% recommended dose of fertilizer (RDF), Vermicompost, 75% RDF, PSB, Azospirillum, Azotobacter and foliar spray of macro and micro elements. Application of 75% RDF (15:10:30 g NPK/10 plants) + Vermicompost (25 g/10 plants) + Azospirillum/ Azotobacter (20 g/10 plants) + PSB (20 g/10 plants) + macro and micro element spray recorded earlier flower bud initiation and flowering. The same treatments conducted to maximum length of flower stalk, thickness of flower stalk, flower diameter, number of flowers/plant and bloom life. It can be concluded that reduced dose of chemical fertilizer (75% RDF) along with application of vermicompost and biofertiizer can improve flower yield of gerbera in open field condition.

Response of Cherry Tomato [Solanum lycopersicum L. var. cerasiforme (Dunnal) A. Gray] to Varied Levels of Nitrogen and Phosphorus Fertigation under Open Field and Polyhouse Conditions

An investigation was carried out at the Department of Horticulture, University of Agricultural Sciences, Bangalore during summer-2017 to study the effect ofvaried levels of nitrogen and phosphorus fertigation on cherry tomato under open field and polyhouse conditions. There were 12 treatment combinations comprising of two growing conditions (open field and polyhouse), three levels of nitrogen (120, 150 and 180 kg N ha-1) and two levels of phosphorus (100 and 120 kg P2O5 ha-1) supplied trough fertigation with recommended potassium (150 kg h-1) as constant which were laid out in Factorial Randomized Complete Block Design with three replications. Result revealed that plant height (384.39 cm), fresh weight per plant (3.00 kg),nitrogen balance index (48.56), total leaf area per plant (6293 cm2), mean fruit weight (15.84 g), TSS content (6.30 ºB) and shelf life (15.66 days) were significantly higher under polyhouse condition with fertigation level of 180:120 kg N:P2O5 ha-1. However, significantly higher yield per hectare (78.16 t), Shelf life (15.66 days) and higher cost benefit ratio (4.81) were observed under open field condition with fertigation level of 150:120 kg N: P2O5 ha-1. Further, it can be concluded from the study that application of 150:120 kg N: P2O5 ha-1 through fertigation under open field condition is profitable during summer season in the Eastern Dry Zone of Karnataka.

Response of horticultural crops under variable microclimatic conditions of different protected cultivation structures

Protected cultivation structures provide favorable environment for crop growth thereby achieving greater yield and high quality produce. The objective of this work was to evaluate the microclimate parameters such as temperature, relative humidity, solar radiation and light intensity underdifferent protected cultivation structures in comparison with open field condition. Four types of protected cultivation structures (polyhouse, walking tunnel,shadenet house and modified greenhouse) were considered for the study. Meteorological data of seven years (2010-2016), recorded on daily basis were used for micro climate analysis of different protected cultivation structures. FAO-56 Penman Monteith approach was used to estimate the reference crop evapotranspiration under different kind of protected cultivation structures.Study shows that walking tunnel, polyhouse and modified greenhouse structures offers a solar energy saver and enhances temperature inside the structures. The total water requirement of drip irrigated crops in protected cultivation structure is reduced by about 25% to 35% under different protected cultivation structures in comparison to open field cultivation. This paper also presents the difference incrop yield grown under protected cultivation structures and open field condition.

Yield, water use efficiency and crop co-efficient of cucumber (Cucumis sativus L.) grown under greenhouse and open field condition

A field experiment was conducted with Chitra variety of cucumber at Agricultural Engineering College and Research Institute, Tamil Nadu Agricultural University, Kumulur in the year 2019-2020. The cucumber seeds were sown under greenhouse and open field condition under drip irrigation system. The micro climatic parameters like maximum and minimum temperature, relative humidity, light intensity were observed. Cucumber plant growth parameters, yield parameters and water use efficiency were recorded. Early flowering and fruit formation (32 days after sowing) was noticed inside greenhouse condition and fruit formation was noticed 40 days after sowing in out-side cultivation. The average length of the fruit was found 20.5 cm inside greenhouse and 17.6 cm for outside cultivation of cucumber. A maximum yield of 11.6 t/ha was recorded inside greenhouse cultivation whereas 7.84 t/ha was recorded for outside cultivation of cucumber. The water use efficiency of 25.7 kg/ha. mm was obtained under green house cultivation whereas water use efficiency of 16.70 kg/ha.mm was recorded in open field cultivation. The crop co-efficient value of 0.67, 0.87, 1.12 and 0.89 were developed for initial, developmental, middle and end stages of crop growth period for open field cultivation. Similarly crop co-efficient value of 0.63, 0.82, 1.05 and 0.88 were developed for initial, developmental, middle and end stages of crop growth period for polyhouse condition of semi arid region.