Heterosis and genetic parameters for yield-related traits in pigeonpea (Cajanus cajan (L.) Millsp.)

Introduction

Pigeon pea (Cajanus cajan (L.) Millsp.) is a major grain legume of the tropics and subtropics, valued for its multipurpose use as food, feed, fodder, and fuel. Belonging to the family Leguminosae, it is a hardy, drought-tolerant, and widely adaptable crop with a maturity range of 90-300 days. In India, it occupies about 4.45 million ha with a production of 4.18 million tonnes and productivity of 937 kg/ha (Anonymous, 2019), ranking second after chickpea. Nutritionally, pigeonpea is rich in protein (17.9-24.3%), carbohydrates, and essential amino acids, and plays a key role in soil fertility improvement through biological nitrogen fixation. Despite its significance, productivity remains low due to limited genetic gain in yield improvement. Understanding the genetic basis of yield and its components is essential for developing highyielding varieties. Generation mean analysis helps partition genetic effects into additive, dominance, and epistatic components, thereby guiding effective breeding strategies. Hence, the present study entitled "Heterosis and Genetic Parameters for Yield-Related Traits in pigeonpea (Cajanus cajan (L.) Millsp.)" was undertaken to assess the nature and magnitude of gene action governing yield and related traits.

Materials and Methods

Experimental materials

The present investigation entitled "Generation mean analysis for yield and its component traits in pigeonpea (Cajanus cajan (L.) Millsp)" was carried out during Kharif 2018-2019 at Agricultural Research Station, Badnapur experimental field. The experimental material used for present investigation comprised of six generations (P 1 , P 2 , F 1 , F 2 , BC 1 and BC 2 ) derived from three crosses involving six parents viz. BDN 708, BDN 711, BSMR 853, BDN 2014-1, BDN 2010-1 and PUSA 2001 along with standard check BDN 716. The characteristic of parents are listed in Table (1.1).

Crossing programme

During kharif 2017 parental materials were sown to undertake crossing programme. Female lines were crossed with each male line viz. BDN 2014-1, BDN 2010-1, PUSA 2001.

Design and Layout

The experiment consisted of three F 1 's and six parents. The detail of experiment is given below: 1. Design: RBD (Randomized Block Design) 2. No. of replication: Two (Two rows each of P 1 , P 2 , F 1 , BC

Testing of six generation of crosses

During kharif 2018, six generations (P 1 , P 2 , F 1 , F 2 , BC 1 and BC 2 ) of three crosses along with one check were sown in Randomized Block Design with two replications on 10 th July 2018. Each replication consisted of six generation (P 1 , P 2 , F 1 , F 2 , BC 1 and BC 2 ) of three crosses along with one check. Each genotype was represented by two rows in each replication. The experimental plot size was 1.80 x 4.00 m 2 (P 1 , P 2 , F 1 , BC 1 , BC 2 generations) and 3.60 x 4.00 m 2 (F 2 generation) spaced 90 cm apart with 20 cm plant to plant distance.

Collection of experimental data

Observations were recorded on randomly selected five plants in parents, F 1, BC 1 and BC 2 generations and 20 plants in F 2 generations in each replication. Data on following characters were recorded.

a. Days to 50% flowering

The number of days required from sowing to flowering of 50% plants in each generation was recorded.

b. Days to maturity

The number of days required from sowing to maturity of crops was recorded.

At maturity, plant height was measured from base of the plant to tip of the main stem.

d. Number of primary branches per plant

The main fruiting branches per plant developed on main shoot were recorded per plant at maturity. Total effective branches on the main stem were recorded.

e. Number of secondary branches per plant

At maturity, the total number of branches was developed on primary branches counted per plant. Total effective branches on the primary branches were recorded.

f. Number of pods per plant

The number of pods retained on plants at the time of harvest was recorded.

g. No. of seeds per pod

The number of seeds in each of 10 pods of selected five plants was recorded and average was worked out as number of seeds per pods on each plant.

The length in each of 10 pods of selected five plants was recorded in cm and average was worked out as pod length on each plant. i. 100 seed weight (g) Healthy 100 seeds were counted and weight recorded in grams.

The grain yield was recorded in grams (g) per plant.

Statistical analysis 4.1. Analysis of variance for treatment differences

To test the significance of differences between treatments, the analysis of variance for Randomized Block Design (RBD) was carried out as per procedure given by Panse and Sukhatme (1967) for all metric characters under study as below,

Number of primary branches per plant

The heterosis over better parent was in the range of -18.68 per cent (BDN 711 X BDN 2010-1) to -6.70 per cent (BDN 708 X BDN 2014-1) and over standard check viz. BDN 716 it was in the range of -11.90 per cent (BDN 711 X BDN 2010-1) to 13.09 per cent (BSMR 853 X PUSA 2001).

Number of secondary branches per plant

The heterosis over better parent was in the range of -12.98 per cent (BDN 711 X BDN 2010-1) to 3.00 per cent (BSMR 853 X PUSA 2001) and over standard check viz. BDN 716 it was in the range of -17.64 per cent (BDN 708 X BDN 2014-1) to -13.44 per cent (BSMR 853 X PUSA 2001).

Number of pods per plant

The heterosis over better parent was in the range of -19.24 per cent (BSMR 853 X PUSA 2001) to 30.38 per cent (BDN 711 X BDN 2010-1) and over standard check viz. BDN 716 it was in the range of 27.19 per cent (BSMR 853 X PUSA 2001) to 36.76 per cent (BDN 708 X BDN 2014-1).

Number of seeds per pod

The heterosis over better parent was in the range of 0.00per cent (BDN 711 X BDN 2010-1) to 23.33 per cent (BSMR 853 X PUSA 2001) and over standard check viz. BDN 716 it was in the range of 19.35 per cent (BSMR 853 X PUSA 2001) to 29.03 per cent (BDN 711 X BDN 2010-1).

The heterosis over better parent was in the range of -3.67 per cent (BDN 711 X BDN 2010-1) to 1.81 per cent (BSMR 853 X PUSA 2001) and over standard check viz. BDN 716 it was in the range of -5.08 per cent (BSMR 853 X PUSA 2001) to 5.08 per cent (BDN 711 X BDN 2010-1).

100-Seed weight (gm)

The heterosis over better parent was in the range of -11.53 per cent (BSMR 853 X PUSA 2001) to 2.16 per cent (BDN 708 X BDN 2014-1) and over standard check viz. BDN 716 it was in the range of -26.31 per cent (BSMR 853 X PUSA 2001) to -19.07 per cent (BDN 711 X BDN 2010-1).

Seed yield per plant

The heterosis over better parent was in the range of -24.14 per cent (BSMR 853 X PUSA 2001) to 27.82 per cent (BDN 711 X BDN 2010-1) and over standard check viz. BDN 716 it was in the range of 7.96 per cent (BSMR 853 X PUSA 2001) to 30.29 per cent (BDN 711 X BDN 2010-1). Overall, the cross BDN 711 × BDN 2010-1 emerged as the most superior hybrid combination with significant positive heterosis for several yield-attributing traits and overall seed yield. This suggests its potential utility in future breeding programs aimed at improving productivity and earliness in pigeon pea.

References

1. Acharya S, Patel JB, Tank CJ, Yadav AS. Heterosis and combining ability studies in Indo-African crosses of pigeonpea. J Food Legumes. 2009;22(2):91-95.
2. Aher GU, Madrap IA, Tike MA, Gore R. Heterosis and inbreeding depression in pigeonpea. J Maharashtra Agric Univ. 2006;31(1):33-37.
3. Deshmukh RB, Rodge RG, Patil JV, Sahane DV. Heterosis for yield and yield components in relation to cropping systems in pigeonpea. Legume Res. 2001;24(2):101-104.
4. Dheva NG, Patil AN, Wanjari KB. Heterosis evaluation in CGMS-based hybrids of pigeonpea. Ann Plant Physiol. 2008;22(2):228-230.
5. Jadhav BD, Nerkar YS. Heterosis for grain yield in pigeonpea grown under different cropping systems. Indian J Agric Sci. 1983;53(7):528-531.
6. Khapre PR, Aghav SB, Madrap IA. Heterosis and combining ability analysis for grain yield and its components in pigeonpea. In: Proceedings of the Seminar on Strategies for Increasing Pulses Production in Maharashtra. 1996. p. 7-8.