Cucurbit research in India: a retrospect 1

Cucurbit research in India: a retrospect 1 M. Rai, S. Pandey, and S. Kumar * Indian Institute of Vegetable Research, P.B. No. 01, P.O. Jakhini (Shahanshahpur) Varanasi 221 305, India * Corresponding author e-mail: sanjeev_iivr@yahoo.com Keywords: Cucurbitaceous vegetables, germplasm, hybrids, production Abstract Cucurbits belong to family Cucurbitaceae, includes about 118 genera and 825 species. In India, a number of major and minor cucurbits are cultivated, which share about 5.6 % of the total vegetable production. They are consumed in various forms i.e., salad (cucumber, gherkins, long melon), sweet (ash gourd, pointed gourd), pickles (gherkins), and deserts (melons). In India, several research institutes and universities have utilized a number of cultivated and wild species to develop improved varieties and parental lines. About 112 open pollinated varieties of several cucurbits have been recommended for cultivation at national and state levels. Among these, 48 improved varieties in 8 major cucurbits have been identified and recommended through All India Coordinated Vegetable Improvement Project. Similarly, 26 hybrids and 7 disease resistant varieties of major cucurbits have also been developed. The main goal of research on cucurbitaceous vegetables in India is to improve productivity on sustainable basis through developing biotic and abiotic resistant variety/hybrids coupled with quality attributes. The yield potential of cucurbits could be increased by adopting the standardized agro-techniques and plant protection measures. INTRODUCTION Cucurbits are vegetable crops belonging to family Cucurbitaceae, which primarily comprised species consumed as food worldwide. The family consists of about 118 genera and 825 species. Although most of them originated in Old World, many species originated in the New World and at least seven genera in both hemispheres. There is tremendous genetic diversity within the family, and the range of adaptation for cucurbit species includes tropical and subtropical regions, arid deserts, and temperate regions. A number of cucurbit vegetables are exported from India (Tab. 1). The genetic diversity in cucurbits extends to both vegetative and reproductive characteristics and considerable range in the monoploid (x) chromosome number including 7 (Cucumis sativus), 11 (Citrullus spp., Momordica spp., Lagenaria spp., Sechium spp., and Trichosanthes spp.), 12 (Benincasa hispida, Coccinia cordifolia, Cucumis spp. other than C. sativus, and Praecitrullus fistulosus), 13 (Luffa spp.), and 20 (Cucurbita spp.). Cucurbits are consumed in various forms i.e., salad (cucumber, gherkins, long melon), sweet (ash gourd, pointed gourd), pickles (gherkins), deserts (melons) and culinary purpose. Some of them e.g. bitter gourd) are well known for their unique medicinal properties. In recent years, abortifacient 1 Cucurbitaceae 2008, Proceedings of the IX th EUCARPIA meeting on genetics and breeding of Cucurbitaceae (Pitrat M, ed), INRA, Avignon (France), May 21-24 th, 2008 285

proteins with ribosome-inhibiting properties have been isolated from several cucurbit species, which include momordicin (from Momordica charantia), trichosanthin (from Trichosanthes kirilowii), and beta-trichosanthin (from Trichosanthes cucumeroides). In India, a number of major and minor cucurbits are cultivated (Tab. 2) in several commercial cropping systems and also as popular kitchen garden crops. Cucurbits share about 5.6 % of the total vegetable production of India and according to FAO estimate, cucurbits were cultivated on about 4,290,000 ha with the productivity of 10.52 t/ha. According to an estimate, India will need to produce 215,000 t of vegetables by 2015 to provide food and nutritional security at individual level and, being a large group of vegetable, cucurbits provide better scope to enhance overall productivity and production. Table 1. Export and import trade of major cucurbits (FAOSTAT 2006) Export (mt) Import (mt) Group of cucurbits % % World India World India share share Cantaloupes & Melons 1,649,698 101 0.01 1,831,147 1,220 0.07 Cucumber & Gherkins 1,615,606 24,096 1.49 1,452,608 0 0.00 Pumpkins, squash & 416,192 - - Gourds 683,761 0 0.00 Watermelons 1,694,872 3,371 0.20 1,623,298 52 0.00 Total 5,376,368 27,568 0.51 5,590,814 1,272 0.02 Table 2. Commonly grown major cucurbits in India English name Scientific name Origin Chr. # (2n) Cucumber Cucumis sativus India 14 Bitter gourd Momordica charantia Indo-Burma 22 Bottle gourd Lagenaria siceraria Ethiopia 22 Watermelon Citrullus lanatus Tropical Africa 22 Melon Cucumis melo Tropical Africa 24 Long/serpent Cucumis melo var. flexuosus India 24 melon Snapmelon Cucumis melo var. momordica India 24 Ridge gourd Luffa acutangula India 26 Sponge gourd Luffa cylindrica India 26 Pumpkin Cucurbita moschata Peru and Mexico 40 Summer Squash Cucurbita pepo Peru and Mexico 40 Winter Squash Cucurbita maxima Peru and Mexico 40 Ash gourd Benincasa hispida South East Asia 24 Pointed gourd Trichosanthes dioica India 22 Ivy or scarlet Coccinia cordifolia (syn. C. India 24 gourd indica) Round melon Praecitrullus fistulosuos Indo-Burma 24 Sweet gourd Momordica cochinchinensis South East Asia 28 286

GENETIC IMPROVEMENT Plant genetic resources management Rich genetic diversity in wild and cultivated species of Luffa, Momordica, Citrullus, Cucumis, Coccinia, Momordica, Cucurbita and Trichosanthes has been augmented. Luffa sp are growing in natural habitat in North-eastern region of India. L. acutangula var. amara occurs in Peninsular India and L. echinata in the western Himalaya and upper Gangetic plains. Another important species, L. graveolens occurs in Bihar, Sikkim, and Tamil Nadu. Momordica balsamina extensively occurs in the semi-dry North-western plains. M. dioica and M. cochinchinensis occur as wild forms in the Gangetic plains (Arora 1995). Trichosanthes has 21 species and is distributed along the Malabar Coast in Western-Ghats and North-Eastern region of India. Trichosanthes cordata is distributed in the Peninsular region. Citrullus colocynthis exhibits a rich diversity in the North-Western plains. In Cucumis, Cucumis hardwickii and Cucumis trigonus (= Cucumis melo) are distributed in the Himalayan belt. There are several cucurbits, which are adapted to a particular region of India. The chow-chow (Sechium edule) has specific adaptation to Mizorum and M. cochinchinensis to Tripura, Assam and West Bengal, and T. dioica to Eastern Uttar Pradesh, Bihar and West Bengal. The Indian Institute of Vegetable Research is a National Active germplasm Site for the systematic management and utilization of germplasm wealth of vegetable crops including cucurbits. The major activity includes collection, evaluation, maintenance and distribution of germplasm. Many of the cucurbit germplasm having unique characteristics have been registered (Rai et al. 2006), as appended in Table 3. Through the National Bureau of Plant Genetic Resources, New Delhi, a number of cultivated and their wild relatives have been introduced from different countries. These include C. lanatus (18 lines from USA), C. melo (25 lines from France and Japan), C. sativus (35 lines from Japan and USA), Cucumis heptadactylus from USA, Cucumis metuliferus (16 lines from USA), Cucumis anguria (94 lines from USA), Cucurbita pepo (22 lines from USA), Cucurbita moschata (4 from Algeria and Japan, 6 from USA), Luffa cylindrica (1 from Japan) and Lagenaria siceraria (1 from Japan,). Several exotic cultivars introduced through NBPGR have directly been adapted for large-scale commercial cultivation in India (Tab. 4). Varietal development The evaluation of indigenous and exotic germplasm introductions, and their hybridization resulted in the selection of 112 superior varieties of different cucurbits. Of these varieties, Hara Madhu of melon, Kalyanpur Baramasi of bitter gourd, Sugar Baby and Arka Jeet of watermelon, Pusa Naveen of bottle gourd, Pusa Vishwas of pumpkin and Japanese Long Green of cucumber are among the popular varieties due to their high yield potential and consumer's preference. As a result of multi-location testing under All India Coordinated Vegetable Improvement Project, 48 improved varieties in 8 major cucurbits have been identified and recommended for cultivation and release in various agro-climatic regions of the country (Tab. 5) (Rai et al. 2004 and 2007). 287

Table 3. Registered germplasm of cucurbits having some unique trait Cucurbit Line National germplasm Registered trait identity no. Pointed IIVR PG- INGR-03035 Parthenocarpic fruits gourd 105 Bitter gourd GY-63 INGR-03037 Gynoecious sex with high yield Watermelon RW-187-2 INGR-01037 High yield and yellow coloured flesh RW-177-2 INGR-01038 Leaf mutant with simple unlobed leaves Bottle gourd Androman- INGR-99009 Andromonoecious sex 6 PBOG-54 INGR-99022 Segmented leaves Cucumber AHC-2 INGR-98017 High yield and long fruit AHC-13 INGR-98018 Small fruit, drought and temperature tolerant Cucumis AHK-119 INGR-98013 High yield and drought tolerance melo var. callosus Roundmelon HT-10 INGR-99038 Tolerant to downy mildew and root rot wilt Snapmelon AHS-10 INGR-98015 High yield and drought tolerance AHS-82 INGR-98016 High yield and drought tolerance B-159 INGR-07044 Downy mildew resistance Table 4. Introductions of cucurbits commercialized in India Crop Introduced variety Country of origin Watermelon Asahi Yamato Japan Sugar Baby USA New Hampshire Midget USA Improved Shipper USA Dexielce USA Cucumber Japanese Long Green Japan Straight eight USA Poinsette USA Summer Australian Green Australia squash Patty pan USA Hybrid development The first F 1 hybrid of watermelon was developed in 1930. Hybrid cultivars are commercialized in selected cucurbits, which express desirable heterosis for yield. In the case of melon, watermelon, cucumber, bottle gourd, several hybrid cultivars have been developed (Tab. 6; Kalloo et al. 2000). 288

Table 5. List of the open pollinated varieties identified/released in India (Kalloo et al. 2006) Crop National level State level Melon Kashi Madhu, Pusa Sarbati, Hara Madhu, Pusa, MHY-5, Madhuras, Punjab Sunehari, Punjab Rasila, Arka Rajhans, Hisar Madhur, RM-43, MHY-3, RM-50, Kashi Madhu Arka Rajhans, Arka Jeet, Durgapura Madhu, NDM-15 Watermelon Durgapura Meetha, Durgapura Kesar, Durgapura Lal Bitter gourd Pumpkin Cucumber Ridge gourd Bottle gourd Sponge gourd Ash gourd Sugar Baby, Arka Manik Priya, RHRBG-4-1, KBG-16, PBIG-1 CM-14, Pusa Vishwas, Arka Chandan, Arka Suryamukh,i CM-350, NDPK-24 Swarna Ageti, Swarna Sheetal, PCUC-28 Swarna Manjari, PRG-7, Arka sumeet Pusa Naveen, OBOG-61, NDBG-104, NDBG-132 Pusa Chikni, CHSG-1, JSGL Kashi Ujawal, Pusa Ujawal Coimbatore long, Pusa Do Mausmi, Pusa, CO-2, Vishesh, Punjab-14, Kalyanpur Baramasi, CO-1 Co-1, Co-2, Narendra Amrit, Kashi Harit, Azad Kaddoo-1 Japanese long green, Straight-8, Pusa Uday, Himangi, Swarna Poorna, Sheetal, CO-1 Swarna Uphar, Co-1, PKM-1, Arka Sujat, Pusa Nasdar, Punjab Sadabahar, Haritham Arka Bahar, Pusa Sandesh, Pusa Summer Prolific Round, Pusa Summer Prolific long, Punjab Round, Punjab Long, Punjab Komal, CO-1, Narendra Rashmi, Narendra Dharidar, Narendra Shishir, Kashi Ganga Pusa Sneha, PSG-9, Rajendra Nenua-1 Kashi Dhawal Table 6. Cucurbit hybrids identified for general cultivation (Kalloo et al. 2000) Crop Hybrid National level State level Melon Pusa Rasraj Punjab Hybrid-1, MHY-3, MHL-10, DMH-4 Watermelon Arka Jyoti RHRWH-12 Cucumber PCUCH-1, Hybrid No.-1, Pusa Sanyog, AAUC-1, AAUC-2 PCUCH-3 Bottle gourd NDBH-4, PBOG-1, PBOG-2 Pusa Manjari, Pusa Hybrid-2, Kashi Bahar Bitter gourd Pusa Hybrid-, NBGH-167 289

Breeding for resistance Cucurbits are highly susceptible to several biotic and abiotic stresses. Resistance sources are generally present in landraces and wild relatives (Tab. 7). Resistance to downy mildew (Pseudoperonospora cubensis) is reported in snap melon (C. melo var. momordica), resistance to fruitfly is reported in C. callosus etc. Most of the resistant varieties in cucurbits have been developed by simple selection (Tab. 8). Table 7. Major biotic stresses and their sources of resistance Crop/ biotic stress Resistance sources Melon Powdery mildew PMR 45, PMR 450, PMR 5, PMR 6, PI 124111 Downy mildew MR-1, PI 414723, DMDR-1, DMDR-2 CGMMV DVRM-1, 2, C. africanus, C. ficifolius, C. anguria Fruitfly C. callosus Nematode C. metuliferus Whitefly C. asper, C. denteri, C. dipsaceus, C. sagittatus Watermelon Fusarium wilt Summit, Conqueror, Charleston gray, Dixilee, Crimson sweet Anthracnose Fair, Charleston gray, Congo, PI 189225 Bottle gourd CMV, SqMV, WMV PI 271353 Fusarium wilt Taiwan variety Renshi Cucumber Anthracnose PI 175111, PI 175120, PI 179676, PI 182445, wise 2757 (USA) Downy mildew B-184, B159, wise 2757 (USA) Powdery mildew PI 200815, PI 200818, C. hardwikkii, wise 2757 (USA) CMV Wisc SMR-12, SMR-15, SMR-18, wise 2757 (USA) Pumpkin PM and Viruses C. lundelliana, C. martenezii ZYMV, WMV C. ecuadorensis, C. faetidistima, C. martenezii CMV=Cucumber mosaic virus, CGMMV=Cucumber green mottle mosaic virus; SqMV- Squash mosaic virus, WMV=Watermelon mosaic virus, ZYMV=Zucchini yellow mosaic virus. Table 8. Resistance varieties developed in cucurbits Cucurbits Varieties developed Resistant to Melon Arka Rajhans Powdery mildew Punjab Rasila, Downy mildew DMDR-2, DMDR-2 DVRM-1, DVRM-2 Cucumber green mottle mosaic virus Watermelon Arka Manik Anthracnose, powdery mildew, downy mildew (multiple resistance) 290

Varieties of bitter gourd (MDU-1) and ridge gourd (PKM-1) have been developed through mutation breeding. Similarly, Pusa Bedana, a triploid watermelon variety is an example of polyploidy breeding in cucurbits. Clonal selection Pointed gourd, Ivy gourd, spine gourd, sweet gourd and bankunari are vegetatively propagated. Therefore, plants derived from a single clone are genetically identical and phenotypically uniform, and also heterozygosity is maintained through clonal propagation. The most important step in clonal selection is creation of variability by assemblage of wide range of clones from different sources. Some varieties of pointed gourd and ivy gourd have been developed by clonal selection. Seedless pointed gourd is selected from a population as clonal selection at IIVR, Varanasi. Pointed gourd clones identified for cultivation includes: Swarna Alaukik, Swarna Rekha, Rajendra Parwal-I, Rajendra Parwal-II, Narendra Parwal-260, Narendra Parwal-307, Narendra Parwal-604, IIVR PG-1, IIVR PG-2, IIVR PG-105. Clone IIVR IG-1 of ivy gourd has also been identified for cultivation. Off season vegetable production Off season vegetable production through nursery management and greenhouse cultivation has been playing an important role in increasing the profit of the farmers. Mulching has been very effective for hybrid crops as it moderate the soil temperatures. During summer and rainy seasons, straw mulch has been found effective. Use the PGR has been proven to be beneficial for earliness, quality and yield in cucurbits. Foliar spray of ethephon (100-500 mg/l), GA (10 mg/l), MH (50-150 mg/l) and TIBA (25-50 mg/l) increase the yield in most of the cucurbits (Sonkar 2003). Staking in cucurbits has been found to be very effective in getting maximum yield and better quality of fruits (Pandey et al. 2001). In this regard, pruning is also beneficial and in cucumber, single stems are allowed to grow with 2-3 fruiting branches, while in melon, lateral branches are removed up to 6-9 nodes, leaving 2-3 fruiting branches. INTEGRATED DISEASE MANAGEMENT Cucurbits are affected by a number of diseases like downy mildew, powdery mildew, gummosis, Phytophthora blight, anthracnose, Cercospora leaf spot, phoma blight, collar rot, Fusarium wilt, white rot, root knot nematode, bacterial wilt, watermelon bud necrosis and leaf distortion virus. These diseases are of national importance and cause important economic losses in cucurbits. Among them, gummosis, anthracnose, Phytophthora blight, Cercospora leaf spot, root knot nematode and watermelon bud necrosis virus are becoming the most destructive diseases in cucurbits (Pandey et al. 2002). Under the All India Coordinated Research Project, a few recommendations have been made to manage downy mildew in melon and cucumber, powdery mildew in melon and anthracnose in watermelon. Melon Spraying of dithane M-45 (0.3 %) at 15 days interval has been recommended to control downy mildew under Ludhiana conditions. 291

Three sprays of calixin (0.05 %) or sulfex (0.25 %) effectively controlled powdery mildew at Rahuri at an interval of 15 days starting from 30-40 days after sowing. Watermelon Recommendations have been made to control anthracnose by spraying benomyl and bavistin (0.2 %) at 15 days interval under Bangalore conditions. Three sprays of 0.2 % miltox or 0.2 % dithane M-45 at 15 days interval has been recommended to control Alternaria blight in Maharashtra. The first spray should be given immediately after the appearance of disease symptoms. Cucumber Five sprays of dithane M-45, dithane Z-78 or aliette (all 0.3 %) at 10 days interval have been recommended to control downy mildew disease under Bangalore conditions. At IIVR, artificial inoculation and screening techniques against some diseases of cucurbits have been developed. Artificial screening is also necessary against different isolates of a particular pathogen collected from various parts of India to get resistance against the multiple races prevalent in different agro climatic zones. Integrated pest management (IPM) Cucurbits are infested with various insect right from the primordial stages of the crop to harvest of the products. Besides the direct damage, many pests act as vector for viruses. Important insect pests of cucurbits are red pumpkin beetle, fruit fly, leaf miner, aphids and mites. Red pumpkin beetle especially attacks the crop at the cotyledonary stage when adults skeletonise the young leaves. During initial infestation, applications of carbaryl (0.1 %) or malathion (0.1 %) suppress the damage successfully. Fruit fly (Bactrocera cucurbitae) is another destructive pest of cucurbits causing direct yield loss. Bitter gourd, melon, sponge gourd and ash gourd are the most preferred hosts of fruit fly. The farmers mostly resort to cover spray, which contaminate the fruits with insecticides. In this context, successful fruitfly management practices have been developed through bait spray consisting of molassess (10 %), insecticide (0.2 %), and yeast hydrolysate (0.1 %). This technique is economical and there is very low contamination of fruits from insecticides. However, along with bait spray, other practices like removal and destruction of maggot in early infested fruits and crop rotation must be adopted. As most of the cucurbits are grown during summer season, the severity of red spider mite is also increasing day by day. In most of the cases, repetitive application of acaricides is required mainly due to the presence of other abandoned hosts harboring population of mite, particularly the old brinjal or okra crop in the vicinity. Therefore, habitat management by removing the alternate non-crop mite reservoirs is needed. Spraying with wet sulfur 80 WP (0.3 %) concentration at 10 days interval reduces the mite infestation. CONCLUSION The main goal of research on Cucurbitaceae in India is to improve productivity on sustainable basis. The breeding programme should shift towards development of biotic and abiotic resistant variety/hybrids coupled with quality attributes. The yield 292

potential of cucurbits could be increased by adopting the standardized agrotechniques and plant protection measures. The value-added breeding approach will add to increase the availability of vegetable by minimizing the post-harvest losses. Considering growing concerns about residue-free vegetables and export of fresh/canned vegetables, it has become imperative to shift to IPM-based practices. In general, productivity is a major criteria to get maximum return but like other vegetable crops, quality and availability of the product during lean periods are also equally important to fetch better price in the markets. Therefore, development of hybrid/varieties with better adaptability under off-season should be undertaken. Further, in order to reduce cost of hybrid seeds it would be appropriate to utilize the available genetic mechanisms for hybrid seed production. In this regard, development of high frequency pistillate lines is advocated. Alternatively, extensive studies on plant growth regulators for large-scale hybrid seed production in many cucurbits should be undertaken. For developing multiple biotic stress resistant lines, validity of already available molecular markers with established linkage may be tested in order to examine their feasible use in breeding programme for development of parental lines. Literature cited Arora RK (1995) Genetic resources of vegetable crops in India: their diversity and conservation, pp.29-39. In Genetic Resources of Vegetable Crops (Rana RS, Gupta PN, Rai M, Kochhar S, eds.), NBPGR, New Delhi, India. FAOSTAT (2006). Available at: http://www.faostat.fao.org. Kalloo G, Baneree MK, Kumar S, Parkash C (2000). Hybrid vegetable technology in India: An overview. In Emerging Scenario of Vegetable Research and Development (Kallo G, Singh K, eds.), Researchco Publishers, New Delhi, pp. 104-117 Kalloo G, Rai M, Kumar R, Prassana HC, Singh M, Kumar S, Singh B, Ram D, Pandey S, Lal H, Rai S, Pandey KK, Sathpathy S (2006) New Vegetable Varieties from IIVR Varanasi. Indian Hort 51(3): 16-22 Pandey KK, Pandey PK, Satpathy S (2002) Integrated management of diseases and insects of tomato, chilli and cole crops Tech. Bull. No. 9. Indian Institute of Vegetable Research, Varanasi, p. 1-22. Pandey S, Ram D (2001). Bower system: Productivity of cucurbits. In. Souvenir: XIX th Group Meet. AICRP Veg. Crops, Indian Institute of Vegetable Research, Varanasi, pp. 23-24 Rai M, Kumar, S., Pandey S, Singh M, Singh, B (2004) Popular Varieties of Vegetable Crops in India. Indian Institute of Vegetable Research Publication, Varanasi, p. 1-93 Rai M, Singh M, Pandey S, Pandey KK, Singh J, Kumar S, Singh B (2006) IIVR: A Decade of Accomplishments, Indian Institute of Vegetable Research Publication, Varanasi, p. 1-37 Rai M, Singh M, Pandey S, Singh B, Yadav D S, Rai, AB, Singh J, Pandey AK, Ram D, Singh N, Rai N (2007) IIVR: Fifteen Years of Accomplishments, Indian Institute of Vegetable Research Publication, Varanasi, pp. 1-45 Sonkar SK (2003) Effect of plant growth regulators on sex expression and yield of pumpkin (Cucurbita moschata Dutch. Ex. Poir.). M.Sc. Thesis, VBS Poorvanchal University, Jaunpur, India. 293

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