Comparative Studies of Intra and Inter Specific Hybrid of F2 Generations in Mungbean

Received Date: Dec 18, 2019 / Accepted Date: Jan 06, 2020 / Published Date: Jan 09, 2020 Abstract Intra and interspecific hybridization was done for developing donor with respect to MYMV and Bruchids resistance. Several differences in many characters were observed in intra and interspecific hybrids crosses for certain characters. Among all the combination of both intra and interspecific crosses studied, single plant yield increased through only intra specific crosses attempted while resistance to biotic stresses like MYMV and bruchids were improved by interspecific crosses. Hence the utilization of wild species in crop improvement is very effective for donor development compared to intra specific crosses.


Introduction
Vigna radiata (L.) wilczek, commonly known as greengram (mungbean) is the most widely distributed one among cultivated Vigna species. Mungbean gives predominant sources of protein and essential amino acids like lysine and tryptophan in vegetarian diets. It is highly drought tolerant and well suited to wide range of soil conditions including light soils and can thrive even under limited irrigation; moreover, it is suited for crop rotation and crop mixtures [1,2]. However, this crop is suffering from the yield advantage as realized in case of C4 cereals. India is the highest producer, consumer and importer in pulses, to get higher yield to create variation through wild hybridization. At present the yield level of greengram as like other pulses is well below the optimum level. The average yield of mungbean is very low not only in India (425 kg/ha) but in entire tropical and subtropical Asia. In Tamil Nadu it is cultivated in an area of 1.63 lakhs hectare with a production of 0.78 lakhs tonnes. Even good quality seeds distributed to the farmers or Page: 2 www.raftpubs.com growers by the departments and university besides management factors the prime cause for the low productivity leads to the inherently low yielding potential of the cultivars coupled with susceptibility to diseases. In the crop improvement programme of mungbean crop we facilitated several ways to do research even then could not achieved the goal due to low variability among the accessions. We need to go to make cross in wild species of Vigna Hopeful to the breeders that utilization of primary, secondary and tertiary gene pools of this crop can result in tremendous improvement in yield. There may be lot chance to when we utilize the variability available in the primary gene pool, it is imperative to critically characterize and evaluate the available germplasm collections in different species , establishing core collections is a good way to identify the diversified materials in the germplasm to eliminate redundancy and employing divergent parents to obtain useful segregants by crossing programme. The core collection concept was suggested by [3], who defined it as a representative sample of a collection where as much as possible of the diversity of the collection, is retained with minimum redundancy.To compare the variability created for yield and yield components among segregants generated through intra and interspecific hybridization.

Materials and Methods
Study of selected crosses of F2 plants from intra and interspecific segregants. The F2 crosses of selected cross combinations from intra and interspecific crosses along with male and female parents with a spacing of 45 x 30 cm during summer 2015 at Agricultural Research Station, Tamil Nadu Agricultural University, Virinjipuram, Vellore. The following crosses in intra specific namely VRM(Gg)1 x Vellore Local, K1 x Pusa bold, VBN1 x Vellore local and VRM(Gg)1 x ML 682 and interspecific crosses viz., V. radiata x V. radiata Var Sublobata, Vigna radiata x V.radiata . mungo var silvestris, Vigna. radiata x Vigna umbellata, Vigna radiata x Vigna. haineana and Vigna radiata x Vigna. trilobata were forwarded to F2 generation to study the frequency of traits and also performance at comparative ways between intra and interspecific crosses The F2s along with their parents of four selected crosses in intraspecfic crosses were sown with a spacing of 30 x 10 cm. All 13 quantitative traits observed in F1 generation was recorded for all the individual plants in the selected F2 generation for both intra and interspecific crosses. Descriptive statistical parameters such as mean, minimum, maximum, variance, SE, SD, skewness and kurtosis were computed. The frequency distribution of F2 segregants of all four crosses for the following traits viz., number of branches per plant, length of branch, number of clusters per branch, number of clusters per plant, number of pods per plant and hundred seed weight which exhibited significant correlation with seed yield were computed and represented as frequency graphs.

Quantitative characters
Thirteen quantitative characters are 1. Plant height (cm), 2. Number of branches per plant 3. Length of branches (cm)4. Days to 50 per cent flowering 5. Number of clusters per branch 6. Number of clusters per plant 7. Number of pods per plant 8. Pod length (cm) 9. Number of seeds per pod 10. Hundred seed weight (g) 11. Grain yield per plant (g) 12. Dry matter production 13. Days to maturity were recorded.

Qualitative characters
To analyse the segregation pattern for morphological traits and to evaluate the level of chromosomal elimination in F2 generation of interspecific crosses, a morphological scoring method was followed in the F2 population , The Qualitative characters were recorded in F1 hybrids and their respective parents such as Stem colour, Stem hairiness, Leaf colour, Leaf shape, flower colour, Mature pods colour, Pods hairiness, Arrangement of the pods, Standard petals colour, Seed colour, Cotyledon colour, Page: 3 www.raftpubs.com Tendril, Seed shape and branching pattern were scored in F2 population.

Result
For comparison of variation generated in the F2 segregants, the frequency distribution graphs were plotted by combining the values of all the F2 progenies irrespective of the crosses. Data on six traits revealed positive correlation with seed yield were plotted. The comparison of skewness kurtosis for intra and interspecific crosses are presented in table 1.  Figure 1A-1C to Figure 7A-7C.
Based on the skewness of frequency distribution the gene action for the seven traits were interpreted and the results for Number of branches per plant for this trait, in the case of intra specific F2 generation the mean value is 1.52 with maximum of 12.00 (Table 2.). The values for skewness high and positive indicating that most of the population distribution is in the negative side as compared to the population mean it is also indicate dominant nature of the alleles. ( Figure 1A). Page: 4 www.raftpubs.com In the interspecific direct crosses, F2 population recorded an overall mean of 1.52 to 4.00 branches per plant (Table 3.). The skewness is positive but less than 1 indicating presence of dominant alleles to a lesser extent. ( Figure 1B).  In the case of interspecific reciprocal crosses of the F2 population mean value was 1.90 with a maximum of 4.00 branches (Table 4.). The skewness was again positive but less than 1 (0.62) indicating presence of lesser extent of dominance. (Figure 1C). Page: 5 www.raftpubs.com    Table 2). The value of skewness is positive and low in magnitude (0.52) indicating that presence of dominant gene action to lesser extent. (Figure 2A).

Figure 2A: Intraspecific crosses.
For interspecific direct crosses the population mean was 16.18 with maximum value of 42.00 ( Table 3). The skewness is negative and low in magnitude (0.01) indicating less extent of additive gene action in the population. ( Figure  2B).  Page: 6 www.raftpubs.com Regarding interspecific reciprocal crosses, the population mean was 23.45 with a maximum of 48.00 (Table 4). The skewness value was positive and low (0.42) reflecting presence a few dominant alleles. (Figure 2C).   In the interspecific direct crosses, the F2 population recorded an overall mean of 2.44 with 8.00 (Table.3). The skewness is positive indicating that presence of dominant alleles to a lesser extent. (Figure 3B).

Figure 3B: Interspecific direct crosses.
In the case of interspecific reciprocal crosses the F2 population mean value was 2.31 with 6.00 (Table 4). The skewness value is positive but less than 1 (0.89) indicating that the population distribution is in the negative side as compared to the population mean. It is indicative dominant nature of the most of the alleles. (Figure 3C).  Page: 7 www.raftpubs.com

Number clusters per plant
For this trait, in the case of intra specific F2 generation, the mean value is 9.06 with maximum of 22.00 (Table 2.). The values for skewness low and positive indicating that most of the population distribution is in the negative side as compared to the population mean it is also indicate dominant nature of most of the alleles. (Figure 4A). In the interspecific direct crosses, F2 population recorded an overall mean of 6.01 with maximum of 45.00 clusters ( Table 3). The skewness is high (5.10) positive indicating presence of dominant alleles. ( Figure 4B).    For interspecific direct crosses the population mean was 6.89 with maximum value of 9.00 ( Table 3). The skewness is negative and low in magnitude (-0.43) indicating less extent of additive gene action in the population. ( Figure  5B). Page: 8 www.raftpubs.com  Hundred seed weight for hundred seed weight, in the intra specific crosses F2 generation mean value is 3.48 with the maximum of 4.90 ( Table  2). The skewness value is low and negative (-0.30) indicating that the population distribution is in the negative side at compared to the population mean. It also indicative additive nature of the most of alleles. (Figure 6A).

Figure 6A: Intraspecific crosses
In the interspecific direct crosses, the F2 population recorded an overall mean of 2.31 with 4.32 ( Table 3). The skewness value (0.70) is positive indicating that presence of dominant alleles to a lesser extent ( Figure 6B). In the case of interspecific reciprocal crosses the F2 populations mean value was 2.81 with 5.00 (Table 4). The skewness value is positive but less than 1 (0.69) indicating that the population distribution is in the negative side as compared to the population mean. It is indicative dominant nature of the most of the alleles ( Figure 6C). Page: 9 www.raftpubs.com   For interspecific direct crosses the population mean was 2.86 with maximum value of 8.52 (Table 3). The skewness is positive and more than 1 (1.18) indicating of additive gene action in the population ( Figure 7B). Regarding interspecific reciprocal crosses, the population mean was 3.19 with a maximum of 6.90 (Table 4). The skewness value was positive and low (0.44) reflecting presence a few dominant alleles ( Figure 7C).

Discussion
The present investigation included the following aspects. Comparison of variability generated in intraspecific and interspecific F2 population for assessment of their breeding value. Field view for intraspecific crosses ( Figure.8). With the objective of the assessing the overall variability generated by the intra and interspecific crosses, the F2 generation frequency distribution graphs were plotted. The