In breeding programmes, variation is an intrinsic part. The results of this research demonstrated a significant amount of variability among genotypes for the majority of the qualitative traits. Variations in characters of okra genotypes viz., leaf lobing, leaf colour, petal colour, petal blotch, mature fruit colour, fruit surface between ridges, fruit constriction of basal part, fruit: shape of fruit apex and fruit axis are depicted in Table 2.
Leaf characters
In the study, the depth of leaf lobing (Fig 1) was found to be 33.4% shallow, 48.3% medium and 18.3% deep in genotypes. Leaf blade serration was 31.7 % weak, 26.6% medium and 41.6% high in the genotypes. Similar reports were reported by
Singh et al., (2015) that 16.67% of shallow, 27.78% of medium and 52.78% of deeply lobed leaves, besides 13.89%, 22.22% and 63.89% of cultivars had weak, medium and strong serration in their leaves, respectively, in his 36 okra cultivars studied.
Colouring of various plant parts
In the present study, variation was expressed in all colour traits studied. The pigmentation of the vegetative (stem and leaf) and reproductive (flower and fruit) organs is remarkably diverse in this study.
Stem colour was recorded as 71.7% green and 28.3% green with a purple tinge for the genotypes, respectively.
Temam et al., (2021) reported 32%, 24% and 44% showing green, green with a purple tinge and purple colour in the okra stems of 36 genotypes studied. In the study, the intensity of colour between veins on the leaf blade was recorded as 38.4% light, 33.3% medium and 28.3% dark.
Singh et al., (2015) found 80.56% light green and 19.44% purple vein colour, as well as 27.78, 50 and 22.22% light, medium and dark intensity green between veins in his 36 okra cultivars tested.
Mature leaf colour was recorded as 43.4% light green and 56.6% dark green for the genotypes. Similarly,
Reddy et al., (2016) reported 80 and 20% of light and dark green colour of mature leaves, in 20 landraces tested.
In the study, petal colour (Fig 2) was observed in the cream (40%) and yellow (60%) petals of the genotypes studied, respectively. Petal base colour (purple) (Fig 3) was recorded at 31.6% inside only and 68.4% on both sides in the study.
Singh et al., (2015) also reported similar results, finding that 11.11 and 88.89% of cream and yellow petals, besides 22.22 and 77.78% of inside purple and both purple petal base colours, among 36 cultivars examined.
Fruit colour observations were recorded for immature and mature fruits. In immature fruit colour, 20% of the genotypes recorded yellowish-green, 41.6% green and 38.4% dark-green fruits. Whereas in mature fruit colour (Fig 4), 8.3% of yellowish-green, 23.3% of green and 68.4% of dark-green fruits were recorded for genotypes.
Binalfew and Alemu (2016) reported that 56.1% had yellowish-green, 25.8% were green, 12.1% were green with red, 3% were dark-green and 3% had dark-red immature fruit colours. Besides, 42.1% had yellowish-green, 1.8% were green, 38.6% were green with red, 14% were dark-green and 3.5% had dark red mature fruit colours in 25 germplasms studied.
Colour traits in okra include vegetative and reproductive structures. These colour features indicate pigmentation in the genotypes’ organs. identified qualitative colour features that are seldom changed by environmental conditions. Due to colour variances, colour attributes are difficult to quantify, even in a homogenous accession. Except for the interior petal blotch, this is true for all green and red varieties. Colour combinations are frequent in okra, with the green or red background being impacted by other colours. Due to the complexity of pigmentation genetics, it is rare to discover a perfectly homogenous accession.
Pubescence (hairiness/spininess) of various plant parts
In this study, diversity was expressed in pubescence traits like stem, leaf, peduncle and fruit (Table 2). This research found that stem pubescence was 56.7% downy, 33.3% slightly rough and 10% prickly for genotypes. In okra,
Reddy et al., (2016) observed 40% downy and 60% slightly rough pubescence.
Leaf pubescence was recorded at 50% slightly rough, 36.7% prickly and 13.3% downy for the genotypes.
Temam et al., (2021) found 86.11% slight, 8.33% glabrous and 5.56% conspicuous leaf pubescence in genotypes. For genotypes, peduncle pubescence was downy with 38.4%, slightly rough with 43.3% and prickly with 18.3%. The peduncle pubescence is novel and no identical discoveries were found.
For genotypes, fruit pubescence was 33.3% of genotypes were downy, 40% slightly rough and 26.7% prickly. The environment, as well as the age of the fruit, impacted the fruit’s hairiness. In 25 okra germplasms investigated,
Binalfew and Alemu (2016) found that 29.6% of fruit pubescence was downy and 35.2% of each was slightly rough and prickly.
Hairy leaves of okra are said to be susceptible to leaf rollers
(Reddy et al., 2016). In contrast, hairy okra genotypes helped lower jassid populations. Although pubescence is commonly utilised in taxonomy, evolutionists and ecologists have mostly neglected its adaptive importance.
Fruit characters
In the study, fruit characteristics like fruit surface between ridges, fruit axis, fruit: position on main stem, fruit: shape of apex and fruit: constriction of basal part expressed large diversity in genotypes (Table 2).
The fruit surface between the ridges (Fig 5) of genotypes varied between concave with 61.7% and flat with 38.3%. The fruit axis (Fig 6) varied greatly in the research, with 83.4% straight and 16.6% curved.
Reddy et al., (2016) observed that 80% and 20% of landraces had concave and flat surfaces between fruit ridges and 85% and 15% of landraces had straight and curved fruit axis, respectively.
Binalfew and Alemu (2016) also reported that 27.3% of the concave and 36.4% of each flat and convex surface between fruit ridges in the accessions tested. The fruits of okra cultivars with concave surfaces between the ridges contain small grooves. Most commercial okra varieties now feature grooves on the sides of the fruits.
Fruit position on the main-stem displays 75% erect and 25% semi-erect positions of fruit on the main-stem in the genotypes studied.
Temam et al., (2021) observed 69.44% erect, 27.78% intermediate and 2.78% horizontal fruit positions on the main stem.
Muluken et al., (2016) reported that erect fruit posture was found in 68% of genotypes, whereas intermediate fruit position was found in 32%. The erect position of fruit on the main stem enhances fruit visibility and adaptability to improve harvest. Erect fruits are simple to pick and snap off the stem. A farmer prefers an erect fruit position on the main stem.
In this study, genotypes displayed variation in fruit shape of apex (Fig 7), with 46.7% narrow acute, 41.6% acute and 11.7% broad acute types of fruit apex. Genotypes displayed great variation in fruit constriction of the basal part (Fig 8), which was reported as 31.6% absent, 38.4% weakly expressed and 30% strongly expressed under the genotypes studied. Similarly,
Singh et al., (2015) reported that 41.67, 47.22 and 11.11% of genotypes showed narrow acute, acute and blunt types of fruit apex. They observed that 13.9% of the basal fruit constriction was absent, 61.11% was weakly expressed and 25.00% was strongly expressed.
Morphological descriptors were developed by various okra researchers based on their perceptions and practical experience observing morphological variation in okra genotypes. The primary advantages of carrying out morphological characterization are that published descriptor lists for major crop species are readily available; it is relatively simple to carry out, simplicity, rapidity and relatively inexpensive assays, even from herbarium specimens and other dead tissues
(Bretting et al., 1995), very easy to identify, can be carried out in situ (on-farm) and does not require special skills in most cases. Lack of polymorphism, environmental interference due to their polygenic nature, large populations of plants, growing the plants to full maturity prior to identification, dependence on crop growth state, masking of recessive characters and limited numbers limit the use and effectiveness of phenotypic characters
(Costa et al., 2009). A new cultivar may also emerge as a result of hybridization between members of popular but genetically similar varietal groupings. The degree of visually visible genetic diversity among newly created cultivars is expected to become even less in this circumstance
(Rahman et al., 2009 and
Priyanka, 2014). This complicates the challenge of precisely recognising novel cultivars using just traditional features. However, the method has remained valuable as a crucial initial step prior to more in-depth biochemical or molecular research in the use of okra germplasm. Morphological characterisation is therefore a highly suggested initial step in any diversity study that should be conducted before further in-depth biochemical or molecular research are used. The use of DNA-based molecular markers allows for a high throughput way of measuring genetic variability between genotypes
(Reddy et al., 2016). India’s okra breeders want a quick, strong and dependable method for variety identification. However, combining isozyme, pigment, morphological and agronomic markers might provide guidance on how to effectively manage landrace germplasm in common okra.
