After reading this article you will learn about:- 1. Origin of Luffa 2. Botany of Luffa 3. Breeding Goals 4. Qualitative Genetics 5. Breeding Methods 6. Seed Production 7. Varieties.
Origin of Luffa:
The Luffa has essentially Old World origin in subtropical Asian region including particularly India.
Botany of Luffa:
The genus Luffa is monoecious with annual vines. Tendrils are branched. Leaves are five to seven lobed, nearly glabrous. Flowers are yellow and showy. There are five petals.
The staminate flowers are in racemes while the pistillate flowers are solitary and short or long pedunculate. Anthers are free. Pistil has three placentae with many ovules. The stigmas are three and bi-lobate. The fruit is oblong or cylindrical. The rind becomes, dry on maturity.
In particular context of L. cylindrica, Whitaker and Davis (1962) have described it as a vigorous vine with slender, five angled stem, deltoid to nearly orbicular leaves in outline, but acutely pointed at the apex, usually three to seven lobed, scrabrous and dentate margins (Fig. 32.1).
Pistillate and staminate flowers may occur in the same leaf axil also. Fruits are nearly cylindrical, 1-2 feet long, straight or curved, normally with light furrows or stripes but not ribbed. Seeds are black, flat, smooth without margins, 10-15 mm long.
The flowers of ridge gourd like those of bottlegourd start anthesis (opening) in the evening and remain open throughout the night and are ready for selfing and pollination in the early morning/ forenoon. The flowers of sponge gourd open in early morning hours and are suitable for selfing/crossing almost throughout the day.
Generally in ridge gourd, the mature unopened staminate and pistillate flower buds are used for crossing in evening and crossed flower buds are covered by paper bag. In sponge gourd, the unopened female and male flower buds are covered in the evening followed by pollination next morning.
Pathak and Singh (1949) were successful in making reciprocal crosses between these two species. The F1plants were generally intermediate between the parents. The F1 showed various irregularities, like, univalents, rings, chains of four chromosomes, chromatin bridges and fragments at metaphase. The percentage of good pollen ranged from 18 to 40%. Thus, the species are not easily crossable and the F1 appears to be of not much practical value.
Breeding Goals of Luffa:
b. High female: male sex ratio
c. Uniform, thick, cylindrical fruits free from bitterness, green/light green
d. Tender, non-fibrous fruits for longer time
e. High fruit yield (high fruit number and weight)
f. Resistance to powdery mildew and downy mildew
Qualitative Genetics of Luffa:
According to Singh (1948), two multiple-allelic loci, A and G, determine sex expression in L. acutangula. They indicated that the F2 of monoecious x hermaphrodite segregated in a di-genic ratio of 9 monoecious: 3 andromonoecious: 3 gynoecious: 1 hermaphrodite forms. Richharia (1948) independently reported similar results regarding the inheritance of sex forms in L. acutangula. Quoting the results of Choudhury and Thakur (1965) on this aspect, Nath (1973) reported similar results in the F2 and backcross generations as given below from the cross of monoecious x hermaphrodite forms in L. acutangula.
The bitterness has been reported to be governed by a single dominant gene Bi. Further, these authors have reported that the corolla colour (orange yellow with green veins of L. cylindrica vs. lemon yellow of L. acutangula), the fruit surface (ridged of L. acutangula), seed surface (pitted vs. non-pitted in L. acutangula), and the type of androecium i.e. stamens, 5 = 2 + 2+ 1 of L. acutangula vs. five free stamens of L. cylindrica were monogenically inherited.
Breeding Methods of Luffa:
(i) Inbreeding and selection
(ii) Crossing of complementary parental lines and handling of segregating generations through pedigree/bulk/backcross/single seed descent method
(iii) Heterosis breeding
Seed Production of Luffa:
The recommended isolation distance is 800 m for breeder/foundation seed and 400 m for certified seed. Roguing for seed production is based on vine and fruit characters. For hybrid seed production, manual mode of pollination is practical in India.
One unit of hybrid seed production plot needs 150 g of female parent seed and 40 g of male parent seed. Hand pollination is used. Hybrid seed production areas in India are Ranibennr in Karnataka, and areas near Jalna in Maharashtra.
Varieties of Luffa:
Co-1, Pusa Nasdar, Pusa Sada Bahar, Satputia (hermaphrodite), Pant Torai 1, Konkan Harita, Punjab Sadabahar.
Pusa Chikni, Kalyanpur Chikni, Pusa Supriya. Light green/white fruited cultivars are preferred in Bihar.
Several hybrids are in market by private seed companies in India. Nandita, Nivedita and Alisa (white fruit and white seeds) of Krishidhan Seeds are popular.