Abstract

Twenty eight genotypes of Indian mustard were grown in four diverse environments to study genotype-environmental ( G X E ) interaction and phenotypic stability for grain yield and its components. Sufficient G E interaction was exhibited by the genotypes for all the characters except oil content ( percentage). However, the characters differed as regards the contribution of linear and non-linear components of GE interaction. The genotypes PBR 181, PBR 171 and PBR 91 have stability for most of the important yield contributing characters as well as seed yield. Thus, these genotypes can be utilized to develop stable strains having wider adaptability in future breeding programmes.

Introduction

The phenotypic performance of a genotype is not necessarily the same under diverse agro-ecological conditions. Some genotypes may far well in some environments but no so well in others. Such GXE interactions have assumed greater importance in Plant Breeding as they reduce the stability of genotypic values under diverse environments. In the present investigation, an attempt has been made to study the stability of some elite promising genotypes of Indian Mustard ( Brassica juncea L. Czern & Coss. ).

Material and methods:

Twenty eight elite genotypes of Indian Mustard were studied for stability parameters under different four environments i.e. under irrigated and rainfed conditions at PAU, Regional Research station, Bathinda, timely sown at PAU, Cotton Seed Farm, Goniana and under late sown conditions at PAU, Regional Research Station, Faridkot during 1996-97. Standard package of practice were followed to raise the crop. Each genotype was accommodated in 1.5 X 5.0 m2 plot in randomized Block design. Observations were recorded on 5 randomly chosen plant in each genotype in replication. Data recorded on primary branches per plant, plant height (cm), main shoot length (cm), number of pods on main shoot length, oil content percentage and grain yield per plot. Stability parameters were estimated using the model proposed by Eberhart and Russel ( 1966).

*Associate Director of Research, PAU, RRS, Bathinda
** Oilseeds Breeder, PAU,RRS, Bathinda
**** Asstt. Plant Breeder< PAU, RRS, Bathinda

Results and discussion;

Pooled analysis of variance revealed significant differences among the genotypes for all the characters. Further, variance due to environment( linear) indicated that performances of the genotypes can be predicted. The variance due G X E was significant for all the characters except oil content percentage ( Table 1.). Stability parameters for different characters are summarized in table 2. The genotype PBR 181, PBR 171 and PBR 91 showed highest mean values of grain yield alongwith the stable performance across different environments. Although, the genotype PBR 148 also showed high grain yield per plot and non-significant regression coefficient, but significance of deviation from regression indicated that the genotype PBR 148 may not exhibit the same level of performance over all the environments.

nly twelve genotypes were found to consistence with respect to number of primary branches per plant.PBR 171, Varuna, RLM 619 PBR 181 and PBR 145 were found to be highly stable for this trait as indicated from non-significant regression coefficient and least deviation from regression. Though PBR 144 had highest mean but significant regression coefficient of this genotype suggested that this genotype performs well only in favorable environments (i.e. timely sown and irrigated conditions). The genotypes PBR 181, PBR 91, Kranti, PBR 154 and PBR 98 were found to be stable over the environments with respect to number of pods on main shoot. Although, PBR 135 showed highest number of pod per main shoot, but this was unpredictable across the environments due to the significant deviation from regression of this genotype. The significant GXE interaction for number of siliqua per plant has also been reported by Wani (1992) in Brassica.

The short statured genotype PBR 154 followed by PBR 141, Kranti, PBR 91 and PBR 98 were found highly stable for plant height across the environments. Similarly for the main shoot length only eight genotypes were found consistence over the different environments. PBR 147 had highest main shoot length but this genotype performed best only in favorable conditions as it indicated from significant regression coefficient of this genotype.

None of the genotype exhibited significant regression with respect to oil content percentage showed that this trait is not influenced by environments. This is supported by the non-significant variance due to G X E interaction for this trait. However, PBR 144 has been found be the most stable for this trait under different environments. Wani (1993) has has also reported that oil content was highly stable trait when genotypes grown across different environments.

From the above discussion, it could be concluded that though no single genotype is stable for all the characters under study. This is in consonance with studies of Wani (1992), Wani (1993) and Verma et al., (1994) as they observed that no single genotype showed stability for all the traits under different environments. But genotypes PBR 181, PBR 171, and PBR 91 have showed stability for most of the important yield contributing characters as well as seed yield. Thus, these genotypes can be utilized to develop stable strains having wider adaptability in future breeding programmes.

References

1. Eberhart, S.A. and W.A.Russel. 1966. Stability parameters for comparing varieties. Crop. Sci., 6:36-40.

2. Verma, A.K.; J.L. Matho and P.K. Sinha. 1994. Stability for yield and yield attributing traits in Toria under rainfed conditions. Indian J. Agric. Sci., (1): 59-61.

3. Wani, S.A. 1992. Genotype x environment interaction for yield and its components in Indian mustard. Adv. Plant Sci., 5: 421-25.

4. Wani, S.A. 1993. Stability for oil content and harvest index in Indian mustard. Adv. Plant Sci., 6 : 65-69.

Table 1. Analysis of variance for different characters in Indian mustard

* : significant at 1% level of probability
** : significant at 5% level of probability

Table 2. Stability parameters in Indian mustard