Genetic Analysis of Green Pod Yield in Table Pea [Pisum sativum var. hortense]

Garden pea [Pisum sativum (L.) var. hortense] belongs to family leguminosae sub family Fabaceae is an important legume vegetable grown throughout the world during cool season. Pea is a self pollinated crop. It is normal diploid crop with chromosome number 2n = 2×= 14. Based on genetic diversity its primary centre of origin is Mediterranean region, Western Asia. Central Asia as secondary centre of origin. It is highly nutritious and capable of using atmospheric nitrogen through symbiosis. It is used as fresh vegetable and processed frozen vegetable in India and abroad. It is good source of vegetarian protein (6.8%-7.2%) which is consumed as green seed. It is a rich source of essential amino acids particularly lysine which is low in cereals. Among the pulses, peas have the highest protein digestibility, being 93.3% as compared to 59.5% to 90.7% in other pulses. It is also rich in carbohydrate, vitamin A and C, calcium and phosphorus. Combining ability is the ability of a genotype to transmit superior performance to its crosses. It is an important plant breeding tools in the selection of suitable parents for hybridization and also helps in the identification of superior cross combination for commercial exploitation of heterosis. The present experiment was conducted to revealed nature of gene action and combinig ability in Diallel mating design to identify potent parents and superior hybrid combination in vegetable pea.

The experimental material comprised 8 diverse genotypes of vegetable pea (Pisum sativum var. hortense) viz. AP-3, KS-280, KS-282, KS-111 AP-1 obtained from vegetable department of, Chandra Shekhar Azad University of Agriculture and Technology, Kanpur. Kashi Mukta, Kashi Nandani and Pant Uphar was obtained from IIVR, Varanasi and GBPUAT, Pant Nagar. A set of 28 crosses were attempted during rabi 2018-2019. Quite good number of crosses were attempted to produce sufficient  F₁ seed in each cross. The 28 crosses along with their 8 parents were grown in randomized block design with 3 replications during rabi 2019-2020. The field chosen was as homogenous as possible. Recommended agronomic practices were adopted to raise a good crop. Each treatment was sown in single row plot of 4 m length. The inter and intra rows spacing was kept 25 cm and 15 cm, respectively. The data were recorded on randomly selected ten plants in each replication for the trait namely days to 50% flowering, plant height (cm), number of branches per plant, Inter-nodal length (cm), first fruiting node, number of pod per cluster, number of pods, green pod yield per plant, pod length, pod width, number of seed per pod and shelling %. The genetic component variance analysed by Hayman (1954a). The combining ability analysis was carried out by the procedure suggested by Griffing’s (1956 b) Method 2, Model 1.

The analysis of variance for parent and F₁’s for all 12 characters was carried out for testing the significance among the treatments. The mean square for all the traits are presented in Table 1. The variance due to treatments were further partitioned into components namely replication, parents, F₁’s and parents Vs F₁’s. Highly significant differences for all the characters were observed among parents and F₁’s. The significant of replication occurs due to moisture stress during growth and development stage of crop. The variances were also  noted for parents v/s F₁’s for days to 50% flowering, plant height, inter-nodal length, number of pods per plant, number of first fruiting node,  number of grain per pod, pod yield per plant while the characters namely, number of  branches per plant, number of pods per cluster, pod width and shelling (%) were non-significant. The significant variance indicating better scope for further improvement of breeding material by selection of promising genotype in crop improvement programme. The significant variance also observed by earlier workers viz. Singh et al., (2017), Lal et al., (2018) and Gupta et al., (2020) for all the characters in table pea.
 

 
Analysis of variance for combining ability
 
The analysis of variance for combining ability for 12 characters  presented in Table 2, revealed highly significant for all yield and its related attributes under study except number of branches per plant and number of pod per cluster. Gupta and Singh (2004) and Kumar et al., (2020) also observed same result in pea. One should proceed for diallel analysis only if the crosses mean sum of square are significant. The further partitioning of mean sum of square into parents, F₁ and parents Vs. F₁ revealed that days to 50% flowering, plant height, inter-nodal length, number  of pods per plant, number of first fruiting node, number of grain per pod, pod yield per plant, pod width and shelling (%) were highly significant (P≤0.01).
 

 
General combining ability effect
 
General combining ability is a measure of additive gene action. GCA is primarily a function of additive genetic variance and additive × additive type epistasis. GCA effect include both additive and additive × additive type of gene action (Griffing, 1956a, b) and Sprague (1966), which represents fixable genetic variance. Based on comparison of  GCA effect with mean performance, good general combiners were KS111 and AP-1 for pod yield per plant, AP-3 and KS280 for days to 50 percentage flowering;  AP-3 and Kashi Nandani for plant height;  Kashi Nandani and AP-3 for number of first fruiting node;  AP-3 and Kashi Mukta for inter-nodal length;  Pant Uphar and KS282 for number of branches per plant;  KS282 for number of pod per cluster; KS280 and KS282 for number of pods per plant; AP-3 and Kashi Nandani for number of grains per pod;  AP-3 and KS280 for pod length; Pant Uphar and KS111 for shelling percentage. It is supported by Bhardwaj and Kohali (1998), Sharma et al., (2000), Gupta and Singh (2004), Kumar et al., (2020) and Amin (2020). Consistent general combining ability effects data presented in Table 3. Varieties KS111 and AP-1S and KS282 showing good general combining ability for yield appear to be worthy of exploitation in practical plant breeding.
 

 
Specific combining ability effect
 
Specific combining ability effects representing non additive component of genetic variance would contribute much for improvement of crops. SCA is function of dominance variance, additive × dominance variance and dominance × dominance type epistasis. Specific combining ability represent dominance and epistasis component of variance which are non fixable and hence, its exploitation in case of commercial exploitation of heterosis is only feasible. On the basis of significant SCA effects data presented in Table 4, showed the good cross combination namely AP-3 × KS282, AP-3 × Pant Uphar and KS282 × Kashi Mukta for days to 50 percentage flowering while Kashi Mukta × Kashi Nandani, Kashi Mukta × Pant Uphar and KS111 and KS111 × AP-1 swere good cross combination for plant height. The good cross combination for inter-nodal length were Kashi Mukta × Pant Uphar, Kashi Mukta × Kashi Nandani and KS280 × AP-1; KS111 v AP-1, KS280 × KS282 and KS280 × AP-1 for number of first fruiting node, while KS282 × Kashi Mukta, KS111 × Pant Uphar and AP-3 × Pant Uphar for number of grains per pod. The good cross combination for pod length were AP-1, AP-3 × Kashi Mukta and KS111 × Pant Uphar and AP-3 × Kashi Nandani, KS111 × Kashi Mukta and KS282 × Kashi Nandani for pod width, while KS280 × Kashi Mukta, AP-1 × Kashi Mukta and AP-1 × Pant Uphar for shelling percentage.
 

       
The good cross combinations for pod yield per plant were KS282 × Kashi Nandani, KS280 × Kashi Nandani and AP-3 × Kashi Nandani. A perusal of these crosses observed for pod yield per plant showed that cross combination KS282 × Kashi Nandani and KS280 × Kashi Nandani had positive and significant SCA effect and high per se performance, the gca effect of parents involved in the cross showed that KS282 had positive and significant GCA status (high) while Kashi Nandini the second parent showed negative and significant GCA status (low) means high × low genetic combination. It indicated that if additive component is good  combiners and complementary epistatic effect present in poor combiners act in same direction can produce transgressive segregants in advance generation which can harvest in terms of yield.
 
The cross combination AP-3 × KS280 was good for four characters viz. plant height, number of grains per pod, pod width and pod yield per plant and genotype KS282 was common in both good general combining ability and good specific combining ability so it can be utilized for further crop improvement programme and may be used for selection of  transgressive segregants. It is supported by Borah (2009), Guleria et al., (2009), Singh et al., (2013), Kalia and Shood (2009), Kumar et al., (2017), Sigh and Dhall (2018).

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