Characterization of Ridge Gourd Germplasm

Abstract : To know about the genetic diversity of 80 accessions of ridge gourd, an experiment was designed in the experimental field of Plant Genetic Resources Centre (PGRC) of Bangladesh Agricultural Research Institute (BARI), Joydebpur, Gazipur, during the Rabi season of 2017-18. Eighty germplasm of ridge gourd were included in the experiment but out of them only 44 germplasm were germinated and among them finally seeds of 40 collections could be collected for characterization. Wide variations were found in both qualitative and quantitative characters among the germplasm and concerning all the characters, the TT-177, AR-197, ATR-18, AHM-215, AC-338, TT-167, AMA-244, KI-38, N-6, RAI-296, AMA-395, AMA-182, TT-26, RC-155, BD-10281 and BD-10282 germplasm were the promising lines for future breeding programs and other research also. germplasm were found as the promising lines. Keywords: Ridge gourd, Characterization, Quantitative analysis Introduction Ridge gourd (Luffa acutangula), an important member of the family Cucurbitaceae grown throughout the country, is a fast-growing vine that often requires some support to facilitate its spread. It is a climbing annual grown primarily for its immature fruits which are eaten raw, pickled or cooked commonly used in soups and curries (Tindall, 1987). The immature fruits which may show morphological differences depending on the cultivar are good sources of vitamin A, B, C and minerals (Morton, 1967; Wills et al., 1984) and has a considerable medicinal importance (Bora et al. 2015) such as Vit-C for keeping away colds, Vit-B for good mood and vitality, zinc for strengthening our immune system, iron for anemia, manganese and magnesium for enzyme production and immunity and calcium and phosphorus for strong bones. As fresh ridge gourd contain folates, in the expectant mothers, this folate-rich food may help in reducing the incidences of neural tube defects in the newborns. The seeds are a good source of iron, magnesium, and phosphorous and contain high amounts of essential amino acids such as lysine (Kamel and Blackman, 1982).Its high fiber content helps with healthy digestion and proper functioning of the excretory system. However, seeds of some varieties are bitter due to high levels of bitter steroids like Cucurbitacin B (Watt and Breyer-Brandwijk, 1962).The pure seed oil is tasteless and contains 68 percent of glycerides of oleic and linoleic acids, thus providing a good substitute for other vegetable oils such as from olive, safflower, and rape seed (Martin, 1979; Girgis and Said, 1968; Kamel and Blackman, 1982). The L. acutangula is believed to be native to the old world tropics (Jeffrey, 1980). India is considered as a primary centre of origin (Chakravarty, 1990). Africa is proposed as a second domestication centre (Potterfield, 1955). L. acutangula has a pan tropic distribution (Tindall, 1987) between latitudes 40 °C and 30 °C South, but mainly around South East Asia, Africa, and South America (Jeffery, 1980). Unlike other cucurbits, it is adapted to hot humid tropics (Purseglove, 1968; Herklot, 1972). However, the area and production of ridge gourd is 9766.39 ha and 47335 metric tons, respectively (BBS, 2016) in Bangladesh. This vegetable grows well in sandy, fertile soils and requires good sunlight and humid conditions to flourish. One hundred and fifty five accessions, 56 new collections and some previous collections are being conserved at PGRC gene bank of BARI, Gazipur. Out of them 133 accessions had been characterized. Hence, the present study has been designed to study the genetic diversity, to identify useful traits and predict their potentiality for utilization and conservation. Materials and methods The study was conducted in the experimental field of Plant Genetic Resources Centre (PGRC) of Bangladesh Agricultural Research Institute (BARI), Joydebpur, Gazipur, during the Rabi season of 2017-18.Althoughabout 80 ridge gourd germplasm were included in the experiment but out of them only 44 germplasm were germinated and among them lastly seeds of 40 collections were obtained due to seasonal problem. The germplasm were collected from different parts of Bangladesh. The seeds were sown in the well prepared seed beds on last 11 November, 2018 and twenty four days old seedlings were transplanted in the pit of main plot whereas the unit plot size was 3X2 m2. The experiment was designed in RCB (Randomized Complete Block) format. Omini and Hossian (1987), working with L. aegyptica observed that potassium containing nutrient treatments (Potassium, Nitrogen-Potassium, and Phosphorous-Potassium) promoted staminate flowering while phosphorous and nitrogen containing treatments (Nitrogen, Phosphorous, Nitrogen-Phosphorous, and Nitrogen-Phosphorous-Potassium) promoted femaleness and reduced staminate flowering. These results are consistent with the findings reported for monoeciuos cucurbits (Hall, 1949; Heslop and Harrison, 1972; Dhaparidze, 1976). That’s why recommended fertilizers were applied as 20 ton/ha cow-dung, 175kg/ha Urea, 175 kg/ha TSP, 150kg/ha MP, 100kg/ha Gypsum, 12.5 kg/ha ZnSO4 and 10 kg/ha Borax stated by Mondal et al., (2011). Moreover, for proper growth and development of the ridge gourd plants, trail was made with bamboo and plastic wire. Picking of matured fruits started from last week of January, 2018 and continued up to February, 2018. Five times weeding and mulching were done at 20 days interval over the experimental period. Over the experimental period some insects and diseases disturbed the plants. To control red pumpkin beetle, mite and leaf miner, Sevin @ 2g/Lit, Vertimec 18 EC @ 1.2 ml/L and Ripcord @ 2 ml/L were applied during seedling and vegetative stage. For controlling leaf blight and root rot disease of ridge gourd, Autostin @ 2g/Lit and Indofil @ 2g/Lit water were applied alternately within 7-10 days interval. Both qualitative and quantitative data were were recorded as per IBPGR descriptor (1981) and those data were subjected to statistical analysis adopting ‘Analysis of Variance’ techniques (Panse and Sukhatme, 1978) using R software to find out the variability among the germplasm. Results and Discussion Qualitative characters Cotyledon size: Among the collection, three different categories of cotyledonous leaf size were found, named as small, medium and large. Observed frequencies of cotyledonous leaf size were significantly different from the frequency of expected number of equal distribution. The expected number of germplasm for an equal distribution was 14.67 (Table 1). Cotyledon colour: Extend of green color of cotyledonous leaves may vary in different genotypes/variety of crops. Thus dark green, light green and mixture of both were observed in the collection (Table 1). Observed distribution of frequencies of germplasm palms of Cotyledonous leaf color was statistically different from the expected number of germplasm for an equal distribution (14.67). Leaf shape: Three shapes of leaf, namely ovate, orbicular and reniform were noticed in the collection. The distribution of genotypes under these three categories was significantly different from the frequency of expected number of equal distribution which was 14.67 (Table 1). The estimated χ2 value was 8.91 which was higher than its criticalvalue. Leaf size: As per descriptor three groups of leaf size were recorded namely small, intermediate and large. Distribution of genotypes under these three categories of leaf size was independent as compared to the expected number of their equal distribution 14.67 (Table 1). The collection of genotypes was dominated by the genotypes with intermediate type leaf size. Leaf margin: All the collected germplasm flourished with dentate type leaf margin (Table 1). Leaf lobe: The leaves of the germplasm were also differentiated for having different depth of lobes observed as shallow, intermediate and deep. Although the germplasm with intermediate type lobe were dominated in the collection (Table 1) but the distribution of germplasm for each group of leaf lobe was not different statistically from the expected number of equal distribution 14.67. The estimated χ2 was 1.27 which was lower than its critical value. Dorsal leaf pubescence: Germplasm were categorized in four classes on the basis of leaf pubescence namely absent, low, intermediate and high (Table 1). The distribution of germplasm for each group of leaf-pubescence was statistically different from the expected number of equal distribution 11. Ventral leaf pubescence: Three types of ventral leaf pubescence named as low, intermediate and high were noticed in the Germplasm. The distribution of germplasm for each group of leaf-pubescence was statistically different from the expected number of equal distribution 11 (Table 1). The estimated χ2 was 14.22 which was higher than the critical χ2 value