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.

Conserving the plant genetic resources through any means is of utmost importance to prevent the loss of plant biodiversity. Long-term storage using liquid nitrogen (LN) is usually adopted for developing long-term base collections of crops for use in the distant future. The fruit crops are commonly propagated through vegetative means and are majorly conserved as ex situ field gene banks, which require large areas and demand intensive field management. The need for repeated reculturing and chances of contamination during subcultures in in vitro banking necessitate a long-term contamination free conservation through cryobanking. Improved cryopreservation techniques will provide added security in the preservation of important woody plant germplasm formerly preserved only as field collections.

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.

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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.