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Effect of rootstock on yield and quality of cucumber scion was studied at Department of Vegetable Science, College of Agriculture, Vellayani, Thiruvananthapuram, Kerala during February-May, 2021. Parthenocarpic and non-parthenocarpic cucumber scions were grafted onto five different cultivated cucurbit species i.e. pumpkin, bottle gourd, oriental pickling melon, culinary melon and ash gourd. Significant variations were observed for all the traits under this study. The highest vine length (4.37 m) was observed in Heera scion grafted onto Lagenaria siceraria rootstock followed by Heera scion grafted onto Cucurbita moschata rootstock (4.13 m). The diameter of rootstock hypocotyl was higher in case of KPCH-1 grafted onto bottle gourd (1.48 mm) and Heera grafted onto bottle gourd (1.43 mm). KPCH-1 grafted on bottle gourd (29.33 days) and culinary melon (31 days) rootstocks showed early female flower initiation. The greater number of fruits was observed in graft combination of KPCH- 1 and bottle gourd (32) followed by parthenocarpic grafts with pumpkin (30.33) and ash gourd (30.33) rootstocks. A greater fruit weight was observed in graft combination of Heera and bottle gourd (7.51 kg) followed by Heera grafted onto pumpkin (7.38 kg). Results of this experiment suggest that these graft combinations can be employed in sustainable vegetable cultivation.

Background: Papaya (Carica papaya L.) belonging to Caricaceae family has long been recognized as a wonder fruit of the tropics and grown predominantly for its delicious taste and extraction of its digestive constituent papain. As vegetative growth and flowering is simultaneous in this crop, supply of requisite amount of nutrients is necessary during the active growth period, which is possible through fertigation. Knowledge on correct dose of fertilizers to be provided through fertigation is very crucial. Methods: A field experiment was conducted during the period 2018-2020 at Instructional Farm, College of Agriculture, Vellayani, Thiruvananthapuram to investigate the response of fertigation and foliar spray on yield and fruit quality of papaya variety Surya. The experiment was laid out in randomised block design with combination of four fertigation doses of 75%, 100%, 125% and 150% RDF of N and K and three foliar sprays (1% 19:19:19, 0.5% ZnSO4+0.3% borax and water spray) which where compared with soil application of recommended dose of NPK (control 1) and soil application of NPK plant-1 year-1 based on soil test data as organic manures as combination of FYM, poultry manure and vermicompost in the ratio of 2:1:1 (control 2). Result: The findings of the study revealed that application of 100% RD of N and K through fertigation at weekly interval from one MAP to 20 MAP and foliar sprays of 0.5% ZnSO4 and 0.3% borax at 4th, 8th, 12th and 16th MAP (T5) along with basal application of 850 g rock phosphate and 15 kg FYM improved the yield and fruit quality parameters and can be recommended for commercial papaya cultivation.

The current changes in fruit production scenario challenged the quality and quantity of fruits required for the vast population. The abiotic and biotic stresses, encountered at critical growth stages and adversely affect productivity of plants. The abiotic stresses like drought, extremes temperature floods and salinity have emerged as major challenges for production of crops. The different abiotic stressescause morphological, anatomical, physiological and biochemical changes and ultimately impacting the productivity and quality of plants. Timely intervention with appropriate adaptation strategies would help in realizing sustainable yields and further enable to overcome adverse effects of abiotic stresses. Successful cultivation of crops and attaining reasonable yields under abiotic stress situations mainly depends on the available adaptation options. Practices like modification in cultural practices, adopting novel irrigation, choice of tolerant rootstocks, choice of tolerant cultivars/crops and biotechnological approaches are to be implemented for alleviating adverse effects. Though, the productivity of fruit crops remains low in areas experiencing abiotic stresses. Therefore, focus is required for developing integrated location-specific and crop- specific adaptation strategies for various abiotic stresses. The integration of all available adaptation options would be the most effective approach in sustaining the production and productivity of fruit crops under abiotic stresses.

Wild plant species related to crop plants form an important source of useful traits for fruit quality improvement and biotic and abiotic stress tolerance. Wide hybridization involving crop wild relatives and related taxa has gained momentum in the recent fruit crop improvement programs. It breaks the species barrier for gene transfer and makes it possible to transfer the genome of one species to another, which results in changes in genotypes and phenotypes of the progenies. The incompatibilities or barriers in wide hybridization occur as prezygotic and postzygotic barriers. Techniques of chromosome doubling, bridging species, protoplast fusion and embryo rescue are highly beneficial in recovering fertile progenies by overcoming various barriers in wide crossings. The present article reviews the techniques involved in distant crossing and their applications in fruit crop improvement.

Vegetables are the richest source of vitamins and minerals and play a major role in nutritional security. The primary objective of vegetable breeding is enhancing production and productivity. Breeders use various conventional and non-conventional breeding approaches for genetic advance. Recent advances in biotechnology helps to enhance the efficiency and shorten the time required to achieve the fixed goals in a breeding program, as well as to address the economic and ecological goals. Among these, haploid (H) and doubled haploid (DH) production through gametic embryogenesis has long been recognized as a valuable tool to help crop improvement. Haploid plants are the sporophytes with a gametophytic chromosome number and doubled haploids (DH) are haploids that have undergone chromosome duplication. Haploids and double haploids occur spontaneously in nature. Haploids can also be induced artificially by various techniques such as wide hybridization, pollination with irradiated pollens androgenesis, gynogenesis and finally further chromosome doubling results in double haploids. Production of double haploids in vegetables will shorten the breeding cycle and also DH technology is useful in reverse breeding, CMS line production, gene stacking and various other genetic studies.

Background: Commercial cultivation of bitter gourd is affected by biotic stresses like mosaic disease, fusarium wilt and root-knot nematode as well as abiotic stress like drought. Grafting with resistant rootstocks can be a tool to control these problems. In vegetable production, grafting is exploited commercially in many parts of the world. The cultivated area of grafted solanaceae and cucubitaceae plants has increased tremendously in recent years because of the advantages of grafted plants. Commercial use of vegetable grafting is a relatively recent innovation in India and scientific information on grafting in bittergourd is meager. In this context, identification of suitable rootstocks and standardization of grafting techniques that do not have adverse effect on yield and fruit quality not only lay foundation for further evaluation on tolerance to different biotic and abiotic stresses but also enhance the area and production of bitter gourd especially in sustainable production systems. Methods: Grafting in bitter gourd was carried out with three grafting methods such as hole insertion grafting, one cotyledon grafting and cleft grafting using growth regulators viz., alar and CCC to control height of rootstocks in order to identify suitable method, growth regulator and its concentration. The grafting experiment was done independently to four cucurbitaceous rootstocks viz., sponge gourd, pumpkin, bottle gourd and bitter gourd using bittergourd var. Preethi as scion. Height and diameter of the rootstocks before grafting were recorded and then the growth regulators alar and CCC each at 10 mgL-1 and 50 mgL-1 along with distilled water as control were sprayed on rootstocks in order to prevent the lodging of the root stocks and then grafted using different methods. Days taken for graft union and percentage success were also evaluated after grafting. Result: Our study of grafting bitter gourd scion into four cucurbitaceous rootstocks utilizing three methods and two growth regulators at two different concentration along with control exhibited significant difference in graft success among the methods as well as concentration of growth regulator in all four experiments. This work can be further utilized for imparting resistance against abiotic and biotic stresses in bitter gourd by selecting suitable rootstocks.

Effects of fertigation and foliar nutrition with micronutrients on papaya flowering, yield and fruit quality parameters were studied during the period 2018 – 2020 at Instructional Farm, College of Agriculture, Vellayani, Thiruvananthapuram, Kerala, India. A field experiment consists of 14 treatments replicated thrice was laid out based on randomized block design. A combination of four fertigation doses of 75 %, 100 %, 125 % and 150 % Recommended Dose of Fertilizers (RDF) of N (304.89, 406.52, 508.15 and 609.78 gm urea plant-1 year-1 respectively based on soil test data in 76 fertigation) and K (426.25, 568.33, 710.42 and 852.50 gm muriate of potash plant?¹ year?¹ respectively based on soil test data in 76 fertigation) and three foliar sprays (1.0 % 19:19:19 at bimonthly interval starting from 4 MAP (Month After Planting) to 16 MAP, 0.5% ZnSO4 + 0.3% borax at 4th, 8th, 12th and 16th MAP and water spray at bimonthly interval starting from 4 MAP to 16 MAP) where compared with soil application of recommended dose of NPK (187:170:341 g NPK plant-1 year-1 based on soil test data) (control 1) and 187:170:341 g NPK plant-1 year-1 based on soil test data as organic manures as combination of FYM (Farm Yard Manure), poultry manure and vermicompost in the ratio of 2:1:1 (control 2). Application of 100 % recommended dose of N and K through fertigation at weekly interval from one MAP to 20 MAP and foliar sprays of 0.5 % ZnSO4 and 0.3 % borax at 4th, 8th, 12th and 16th MAP (T5) initiated earliness in flowering (142.67 days) and harvest (275.00 days). However, plants receiving 100 % recommended dose of N and K through fertigation at weekly interval from one MAP to 20 MAP with foliar sprays of 1% 19:19:19 at bimonthly interval starting from 4 MAP to 16 MAP (T4) significantly improved the fruit weight, number of fruits per plant and total yield per plant in papaya variety ‘Surya’ and it was on par with T5. Fruit quality parameters namely TSS (Total Soluble Solids), ascorbic acid and total sugars were found significantly highest in T5 and lowest titratable acidity was also recorded in T5. Hence, treatment T5 which is found superior in initiating early harvest, with higher yield and good quality characters in papaya variety ‘Surya’ can be recommended to farmers.