Genetic Dissection of Variability Using Morphological Traits in Drumstick (Moringa oleifera Lam.) Genotypes

Twenty one moringa genotypes that were collected from different geographical regions of India were evaluated for variability, heritability and genetic advance for growth, yield and earliness characters and significant variations were recorded for the investigated traits. Widest range of variation was observed in pod length, number of pods per plant, single pod weight and pod yield per plant. Maximum genotypic and phenotypic coefficient of variation was observed for number of primary branches, pod length, number of pods per cluster, single pod weight and pod yield per plant. Higher value of heritability associated with high genetic advance as percent mean was observed for pod yield per plant, single pod weight, pod length, plant height, leaf length, pod girth, number of pod per cluster and number of branches per inflorescence. High heritability and genetic advance indicating additive gene action suggested that simple selection could be effective for the improvement of these traits.

. Drumstick is an important food commodity which has had enormous attention as the "natural nutrition of the tropics". It is an exceptionally nutritious vegetable tree with multiple uses and beneficial properties and has therefore been called a "miracle tree" (Fuglie, 1999) or "one of the world"s most useful trees" (Lea, 2010).
The miracle tree is a perennial softwood crop native to the sub-Himalayan ranges of India, Pakistan, Bangladesh and Afghanistan (Fahey, 2005). It is widely grown in the tropics of Asia, Latin America, the Caribbean, Florida and the Pacific Islands to West, East, and South Africa. India is the prime producer of Moringa (Drumstick) with an annual production of 2.20 to 2.40 million tonnes of tender fruits from an area of 38,000ha leading to the productivity of around 63 tonnes per ha.5 Among the different states, Andhra Pradesh leads in both area and production (15,665ha) followed by Karnataka (10,280ha) and Tamil Nadu (13250ha). In other states, it occupies an area of 4,613ha.
Moringa oleifera is a fastgrowing, drought-resistant tree with many medicinal properties. Common names include moringa, drumstick tree (from the long, slender, triangular seedpods), horseradish tree (from the taste of the roots, which resembles horseradish), and ben oil tree or benzolive tree. Flower favors cross pollination due to delayed stigma receptivity. The successful pollination requires large number of insect population, among which Xylocopa is most important. The zygomorphic gullet type flowers show a forenoon (6.00 h -12.00 h) pattern of anthesis after which pollen anthesis takes place (7.00 h -13.00 h) (Bhattacharya and Mandal, 2004). It is widely cultivated for its young seed pods and leaves, used as vegetables, for traditional herbal medicine and also used for water purification.
Moringa has many medicinal properties. Almost all parts viz., root, bark, gum, leaf, fruit (pod), flower, seed and seed oil have been used for treatment of various inflammation and infectious diseases along with cardiovascular, gastrointestinal, haematological and hepatorenal, disorders (Singh et al., 2011). Flowers are used as stimulant, tonic and diuretic. They are useful in increasing the flow of bile. The seeds of Moringa are considered to be antipyretic, acrid, bitter (Oliveira et al., 1999) and reported to show antimicrobial activity. The seeds of Moringa are used as water purifier. The oil extracted from the seed known as "Ben" is used as lubricant in watches, for edible purpose and in cosmetics. The kernel of the seed is rich in crude protein, fatty oil and fiber. Leaves contain 4.0per cent moisture, 38.4per cent crude protein, 34.17per cent fatty oil, 3.5 per cent fibre and 3.2 per cent mineral matter.
Germplasm evaluation and characterization for economically important traits are basic prerequisite for crop improvement. For any crop improvement programme, evaluation of germplasm to assess the existing variability is the first step. Greater the variability present in the initial material better would be the chances for evolving desired types. A clear understanding of variability of various characters of the breeding materials is an asset to the plant breeder for selecting superior genotypes on the basis of their phenotypic expression. The diversity in moringa genotypes presents an opportunity for selection of superior types and improvement of different quantitative and qualitative characters. The determination of genetic variability and its partitioning into various components is necessary to have an insight into the genetic nature of yield and its components. In this regards, estimates of genotypic and phenotypic variance for various quantitative characters along with heritability and genetic advance expected by selection for yield and its components are useful in designing an effective breeding programme.

MATERIALS AND METHODS
The study has taken up in the education and research block of Department of biotechnology and crop improvement, College of horticulture, University of horticultural sciences, Bagalkot. Twenty-one genotypes of Moringa oleifera used in the present study were collected from different eco-geographical locations covering different states of India were studied in Randomized block design in three replications (Table 1). The observation were recorded for twenty one different quantitative morphological parameters viz., plant height, tree girth, number of primary branches, leaf length, petiole length, days to flower initiation, inflorescence length, number of branches per inflorescence, flower size, number of pods per plant, pod length, pod girth, number of pods per cluster, number of pods per branch, days to pod initiation, days to pod maturity, single pod weight, number of seeds per pod, seed size, hundred seed weight and pod yield per plant. The data collected on all the characters were subjected to standard methods of analysis of variance (ANOVA) (Panse & Sukhatme, 1985). Genotypic and phenotypic co-efficient of variation were estimated according to Burton (1952) GCV and PCV were classified by Sivasubramanian and Madhamenon (1973). Heritability and genetic advance as per cent of mean was calculated based on Johnson et al. (1955).

RESULT AND DISCUSSION
The analysis of variance revealed the existence of significant differences among the genotypes for all the traits, indicating the presence of considerable genetic variability among the experimental material under study (Table 2). Thus, there is a plenty of area and scope for the improvement of different quantitative and qualitative traits through selection. The tendency of individual genetic characteristics in a population to vary from one another. Similarly highly significant variation for all characters studied was reported by Raja and Bagle (2003), Selvakumari et al. (2013), Varma et al. (2019), Priya et al. (2019) and Balaguru et al. (2020). The mean performance, range and general mean of twenty one genotypes of drumstick for twenty one quantitative characters studied are presented in Table 3. Range of variation observed for all the traits in the present study indicated the presence of sufficient amount of variation among the genotypes for all the characters studied.  (2003) Heritability is the portion of phenotypic variation which is transmitted from parent to the progeny. High heritability was recorded for all the characters except number of primary branches, inflorescence length, seed size and hundred seed weight (Table 3). The higher broad sense heritability was recorded for pod length (94.8 per cent) followed by pod yield per plant (93.0 per cent), number of pods per plant (91.9 per cent), pod girth (91.5 per cent), plant height (91.4 per cent), days to flower initiation (91.3 per cent) etc., Higher heritability in broad sense showed that large proportion of phenotypic variance was attributable to the genotypic variance and these traits were less affected by the environment.
The least heritability was reported for number of primary branches (33.7 per cent) followed by hundred seed weight (46.2 per cent) and inflorescence length (46.8 per cent).
Heritability estimates along with genetic advance is more useful than the heritability value alone for selecting the best individual. Higher value of heritability associated with high genetic advance as percent mean was observed for pod yield per plant, single pod weight, pod length, plant height, leaf length, pod girth, number of pod per cluster and number of branches per inflorescence. This is attributed to the additive gene action. Heritability values were high than those of genetic advance for most of the traits which indicated that they were least influenced by the environment and shows that the phenotypes were true representative of their genotypes and selection based on phenotypic performance would be reliable genotypes which is in line with the findings of Karunakar et al. (2018), Lakshmi Narayana Priya et al. (2019 and Varma et al. (2019).  Heritability estimates along with genetic advance is more useful than the heritability value alone for selecting the best individual. Higher value of heritability associated with high genetic advance as percent mean was observed for pod yield per plant, single pod weight, pod length, plant height, leaf length, pod girth, number of pod per cluster and number of branches per inflorescence. This is attributed to the additive gene action. Heritability values were high than those of genetic advance for most of the traits which indicated that they were least influenced by the environment and shows that the phenotypes were true representative of their genotypes and selection based on phenotypic performance would be reliable genotypes which is in line with the findings of Karunakar et al. (2018), Lakshmi Narayana Priya et al. (2019) and Varma et al. (2019). Selection would be depending on pod yield per plant, the number of pods per plant, single pod weight and pod length may bring out the genetic improvement in the moringa because they showed a high value of GCV, PCV, heritability and genetic gain. Hence the selection will be effective for these traits. These traits can be improved through mass selection, progeny selection, or any other modified selection procedures. It can be concluded that PKM-01, PKM-02, Dhanraj, Shirdi-01 and Bagalkot-01genotypes, performances were outstanding for the traits like pod length, number of pods per plant, single pod weight and pod yield per plant, indicating their utilization in the breeding for development of elite varieties or hybrids in the future and genotypes like Bhagya, Tangi-01 and PKM-02 for better performance in relation to earliness parameters.