Expedition, Collection and Evaluation of Rajmash (Phaseolus vulgaris L.) Folk Germplasm Accessions Collected from Eastern Ghats of Andhra Pradesh for Genetic Variability and Heritability Studies

Rajmash or Indian field bean (Phaseolus vulgaris L.) is an important food legume in the world (Blair et al., 2011). Rajmash is native of central and south America and widely cultivated in temperate and subtropical regions of the world (Zeven et al., 1999).  Rajmash (2n= 2x=22) belongs to family Leguminosae. The other vernacular names of Rajmash are Indian field bean, snap bean, kidney bean, haricot bean.  Rajmash seeds are rich in protein, fibre, starch and minerals like iron, potassium, manganese, magnesium (Broughton et al., 2003). Further, it is also rich in bioactive compounds, viz. phenolic compounds, lectins, phytates, etc. (Kumar et al., 2008). The Eastern ghats of Andhra pradesh ie., Araku region is a rich source of diversified germplasm in legumes, medicinal plants, millets and ancient crops (Sirisha., 2022).  In tribal areas, it is used as one of the important pulse crops and widely grown as mixed crop along with paddy, maize or pure crop after maize. Several landraces of Rajmash beans grown by farmers, vary in shape, size, taste, maturity and in nutritive values (Thirugnanavel et al., 2019).  Conservation and utilization of this rich genetic wealth of Rajmash bean is a major challenge. The main objective of this research is to collect the germplasm accessions and landraces from the tribal farmers of eastern ghats of Andhra Pradesh.  In the present study germplasm exploration, collection and conservation of Rajmash folk accessions or landraces was carried out along with the pass port data.  The variability, heritability studies in collected germplasm accessions of Rajmash is carried out to further utilize in the breeding programme.

Expedition and collection
 
The eastern ghats of Andhra Pradesh include Araku, chintapalle, G.K.Veedhi, Paderu  areas located in Alluri Sitaramaraju district  with rich biodiversity of germplasm of many crop and wild species exists. This region is located at a mean sea level of 1800 to 3000 m. Initial survey conducted with the local tribal people regarding the season of growing, availability and area to be explored for collection of the rajmash land races. The germplasm accessions are collected during the Kharif  in the month of July 2021. Approach to local tribal farmers is channelized through scientific staff of Regional Agricultural Research Station, Chintapalli. Exploration is carried out and 70 folk land races were collected along with GPS co-oridnates using hand held GPS machine (Garmin etrex 30x) from different villages of Chintapalle, G.Madugula, G.K.Veedi mandals etc. Bulk and random sampling methods were adopted for collecting the germplasm (Table 1).  As per the standard procedures provided by ICAR-NBPGR, New Delhi, Passport data of each accession line was collected from different villages of Chintapalle, G.Madugula, G.K.Veedi mandals etc. The procedure is referred by the authors Pareek et al., 2000, Kanwar and Mehta (2018), Sirisha (2022).  Data on test weight, colour and size of the germplasm accessions are studied and recorded. (Table 1).


 
Evaluation
 
Evaluation of these 70 rajmash germplasm accessions collected after exploration are sown in augmented block design in two blocks along with three checks conducted during Rabi 2021 and 2022 for two seasons. The mean performance of the two seasons is presented in Table 2. Each germplasm accession is sown in three rows each of 4m row length with 30 x 10 cm spacing.  The experiment is conducted at Acharya N G Ranaga, Regional Agricultural Research Station, Chintapalli andhra Pradesh. The germplasm lines are characterized for important yield attributing characters with the descriptor list and conserved for the further study.  The discussion is in accordance with Kanwar and Mehta (2018), Sirisha (2022).  All the germplasm accessions are evaluated and studied for the yield attributing characters i.e., days to 50 % flowering, plant height, number of pods per plant, pod length, number of seeds per pod, test weight and grain yield kg/ha. The mean performance of the two seasons is depicted in Table 2.


 
Statistical analysis
 
Data is statistically analyzed for phenotypic coefficient of variation (PCV), genotypic coefficient variation (GCV), (Burton, 1952), genetic advance as per cent mean (Johnson et al., 1955) and heritability (Allard ,1960). Statistical analysis is carried out using SPAR 2.0. (Ahuja et al., 2008).

Expedition and collection
 
The germplasm accessions are collected along with the passport data along with GPS co-ordinates. (Table 1). Rajmash germplasm accessions are collected at 170 and 18o North latitude and  82o  East  longitude and elevation  ranging  from 2500  m to 3500 m from the mean sea level. (Table 1) (Sirisha, 2022). Test weight of the rajmash accessions ranged from minimum of 8 g (CTPL RJM 2021-02) to maximum of 41.5 g (CTPL RJM 2021-02).  A wide range of variability is observed in colour ranging from maroon red, red, brown, light brown, black, beige, variegated. A wide range of variability is also observed in size from small, medium and big size. The results are depicted Table 1, Fig 1. Similar results are recorded by Dar  et al., 2009, Sirisha (2022).


 
Performance, variability and heritability studies of the germplasm accessions
 
All the 70 folk germplasm accessions collected during Kharif 2021 and evaluated in two seasons i.e., Rabi 2021 and 2022. Among the 70 germplasm accessions collected, 10 germplasm accessions not germinated. Remaining sixty germplasm accessions are studied and the mean performance of the germplasm accessions are presented in Table 2.  As per the ANOVA Table 3 the treatments, checks, checks, checks+ var vs, entries checks vs varieties recorded statistical significant difference among the genotypes. (Table 3)


       
Heritability, genetic advance as percent mean at 5% level and gene action for the yield attributing parameters are discussed hereunder in detail as depicted in the Table 4.


 
Days to 50% flowering
 
Range of variation for this character ranged from 26 days (CTPL-RJM 2021-61) to 55 days (CTPL-RJM-2021-29) with a mean of 55 days and showed moderate PCV (15.09%) and GCV (14.29%). High heritability (89.72 %) coupled with moderate genetic advance of percent mean (27.89%) indicating the operation of both additive and non-additive gene action, this trait may be improved by mass and progeny selection Ahmed (2011); Iqbal et al., (2011).
 
Plant height
 
This parameter ranged from 12.9 cm (CTPL-RJM 2021-24) to 164.5 cm (CTPL-RJM 2021-07) with a mean of 66.7 cm. PCV (69.26%) and GCV (68.65%) is high. High heritability (98.23%) coupled with high genetic advance as % mean (140.164%) was recorded. Additive gene action is observed which can be improved with simple selection.
 
Number of pods per plant
 
This character showed a range of variation from one (CTPL-Red) to sixteen (CTPL-RJM 2021-36) number of pods with a mean of six pods per plant.  The PCV (33.38%) and GCV (28.66%) is high. High heritability (73.72%) and high genetic advance per cent mean (50.69) is observed indicating the operation of additive gene action in which simple selection may be operated for improving the trait. (Ahmed, 2011; Iqbal et al., 2011).
 
Pod length
 
The parameter recorded range of variation from 6.0 cm to 13.02 cm with a mean of 9.90 cm. PCV (11.36%) and GCV (10.03%) is moderate. High heritability (77.96%) coupled with moderate genetic advance as % mean (18.85%) was recorded.  Both additive and non-additive gene effects observed may be improved through mass selection, progeny selection.

Number of seeds per pod
 
Recorded a range of variation from 3 (CTPL-RJM 2021-24, 42,55, Jwala) -8 (CTPL-RJM 2021-31) number of seeds with a mean of 5 seeds per pod. PCV (26.16%) and GCV (24.97%) is high.  High heritability 91.12% with high (49.10%) genetic advance percent mean is observed indicating the operation of additive gene action.
 
Test weight
 
Showed a wide range of variation from 8.5 g (CTPL-RJM-2021-42) to 52 g (CTPL-RJM-2021-64) with a mean of 30 g. High PCV (29.48%) and high GCV (28.73%). High heritability (94.94%) recorded with high genetic advance as % mean (57.67%) shows additive gene action.
 
Grain yield (kg/ha)
 
In rajmash germplasm accessions shown a wide range of variation minimum of 109 g (CTPL RJM 2021-04) to 2146 g (CTPL-RJM-2021-07) with a mean grain yield of 670 g.  High GCV (63.94%) and high PCV (64.34%) is recorded with high heritability (98.76 %) and high genetic advance of per cent mean (130.92%) showing additive gene action.  The character may be improved by simple selection.  Similar results are coded by Ahmed, (2011), Iqbal et al., (2011), Nimbalkar et al., (2002), Chaudhary et al., (2001), Singh and Sharma (2014). The germplasm accessions are evaluated with three checks (CTPL red, Jwala and Utkarsh).  The germplasm accessions CTPL-RJM-2021-65 (1842 kg/ha) and CTPL-RJM-2021-07 (2146kg/ha) recorded significant highest grain yield when compared with the best check Jwala (1477 kg/ha). Forty genotypes recorded highest significant grain yield kg/ha when compared with the local check CTPL Red (368 kg/ha).  These accessions may be utilized in the breeding programmes to improve grain yields.  All the germplasm lines are conserved for future breeding programme. The genotypes are also further studied for important characters and submitted to national repository for further utilization.

The biodiverse rajmash folk germplasm accessions were collected from the eastern ghats of Andhra Pradesh and evaluated for important yield attributing characters, heritability and genetic advance as percent mean. A wide range of variability observed in seed colour, size, seed yield, test weight. High heritability is also observed for all the characters. Among all the germplasm accessions germplasm accessions CTPL-RJM-2021-07 (2146kg/ha) and CTPL-RJM-2021-65 (1842 kg/ha) recorded significant highest grain yield when compared with the best check Jwala (1477 kg/ha). These accessions may be utilized in the breeding programme for further development of the varieties in rajmash. Forty genotypes recorded highest significant grain yield kg/ha when compared with the local check CTPL Red (368 kg/ha).  The collected germplasm is further evaluated and submitted for the national germplasm repository for further conservation.

The authors are highly thankful to the Acharya N.G. Ranga Agricultural University, for providing funding to carry out the work and local tribal farmers for assisting in conduct of the  exploration. 
 
Disclaimers
 
The views and conclusions expressed in this article are solely those of the authors and do not necessarily represent the views of their affiliated institutions. The authors are responsible for the accuracy and completeness of the information provided, but do not accept any liability for any direct or indirect losses resulting from the use of this content.
 
Informed consent
 
All animal procedures for experiments were approved by the Committee of Experimental Animal care and handling techniques were approved by the University. (Not applicable to this article).

The authors declare that there are no conflicts of interest regarding the publication of this article. No funding or sponsorship influenced the design of the study, data collection, analysis, decision to  publish, or preparation of the manuscript.