Int. J. Life. Sci. Scienti. Res., 2(2): 127-129, March 2016
Selection Indices for Yield and Attributing Characters Improvement in Pigeon pea (Cajanus cajan L. Millspugh)
S.RAJAMANI, M.SREEKANTH, V.SAIDA NAIK and M. RATNAM
REGIONAL AGRICULTURAL RESEARCH STATION, LAM
ACHARYA N G RANGA AGRICULTURAL UNIVERSITY,GUNTUR, Andhra Pradesh 522 034.
ABSTRACT- Twenty two selection indices involving seed yield and six yield components were constructed using the discriminatnt function technique. The efficiency of selection increased with the inclusion of more number of the characters in the index. Selection indices were constructed adapting discriminant function which indicated that the maximum genetic advance and relative efficiency can be obtained when seed yield was included as one of the characters in combination with all other characters viz., plant height, days to 50% flowering, number of primary branches per plant, number of secondary branches per plant, number of pods per plant and test weight. However higher relative efficiency was obtained when a function yield was included as one of the component character in combination with number of pods per plant, number of secondary branches per plant and test weight than to a function with all the character in combination with yield.
INTRODUCTION- Pigeonpea is the second important pulse crop of India grown in around 4.5 m. ha with an average productivity of 700 kg per ha which is below world productivity of one tonne per ha. Yield is a complex character and governed by poly genes. Yield is subjected to environmental fluctuations and the performance of individual plant is consequently is not a reliable index of the genotype [1]. Study of discriminant function for yield alone does not result in expected yield. Success of selection would be enhanced by use of selection techniques as it facilitates simultaneous improvement of number of characters [2]. Selection index is most widely used selection method for selection which can be used for more than one character. The superiority of index increases with increasing number of traits under selection but decreases with increasing differences in relative importance. The superiority of selection index is maximum when the traits considered are equally important.
MATERIAL AND METHODS- Twenty two genotypes received from all over India were utilized for the study to formulate selection indices. The material was raised in randomized block design during July 2014 at Regional Agricultural research Station, Lam, Guntur. A total 693.9 mm rainfall was received during entire period of crop season. Crop was sown in the month of July and harvesting was completed in the month of February, 2015. The observations were recorded on five competitive plants from each replication for plant height, days to 50% flowering, number of primary branches, number of secondary branches, number of pods per plant, test weight and yield. The mean data was subjected to analysis of variance and selection indices were formulated. The expected genetic advance from different selection indices at 5% selection intensity and relative efficiency of each selection function over straight selection was also calculated. The reciprocals of means of each character were used as relative weights of corresponding character by [3]. The expected genetic advance, by constructing different discriminant functions was calculated and relative efficiency of each discriminant function was estimated as per [4]. The relative efficiency of discriminant function which includes yield per plant alone was taken as 100% and the relative efficiency of other functions were estimated.
RESULTS AND DISCUSSION- The data on weighing coefficients and genetic advance for each character was estimated to assess extent contribution of each character towards yield. Among the characters days to 50% flowering recorded the highest weightage of (9.720) followed by number of pods per plant (0.604) and the least weightage was recorded by test weight (-84.452). The weightage coefficients (β1) for seven characters were given in the table 1. Discriminant function with index of genetic advance as well as relative efficiency over grain yield was computed for seven characters viz., plant height (cm), days to 50% flowering, number of primary branches per plant , number of secondary branches for plant, number pods per plant, test weight (g) and yield (Kg/ha) (Table 2).
Table 1. Weighing coefficients (b1), economic weight and genetic advance for different characters in pigeonpea
S noCharacterEconomic weightWeighing coefficient (β1)Variance phenotypicalGenetic advance
1Plant height (cm)1.000-2.935-362.468-1.031
2Days to 50% flower1.0009.720142.0800.404
3Primary branches/plant1.000-6.5576.9830.019
4Secondary branches/plant1.000-20.80445.0000.128
5Pods/plant1.0000.6045406.461815.387
6Test weight (g)1.000-84.452-162.0741-0.4613
7Yield (kg/ha)1.0000.566118381.743336.919
Table 2. Selection indices along with their genetic advance and relative efficiency in pigeonpea
codeyieldPlant height (cm)Days to 50% flowerPrimary branches/plantSecondary branches/plantPods/plantTest weight (g)Genetic advancementSelection intensity5%% gain over 1st variable
10.624------------328.49676.70100.0 %
20.3465.7611.861.75%
30.9796.0812.521.85
40.5320.190.400.06%
50.5980.951.970.29%
60.34931.8665.639.7%
70.7990.931.920.28%
120.623-2.314----------329.43678.63100.2 %
160.632--------0.457--340.64701.72103.7 %
1260.628-2.356------0.546--341.72703.94104.0 %
1670.592--------0.444-48.113344.20709.04104.7 %
12670.585-2.558------0.538-58.652345.85712.45105.2 %
13670.576--7.631----0.449-65.983346.44713.68105.4 %
15670.596-------25.83620.500-58.187346.58713.96105.5 %
123670.561-3.20010.255----0.565-77.157349.77720.52106.4 %
1234670.561-3.16010.276-7.1564--0.567-78.009349.80720.58106.4 %
1235670.567-2.9719.699---20.8180.602-83.671351.34723.76106.9 %
12345670.566-2.9359.720-6.557-20.8040.604-84.452351.37723.81106.9 %
Economic weights1.01.01.01.01.01.01.0
[5] stated that the superiority of selection based on selection index increased with increase in number of characters under selection. In the present study the relative efficiencies of selection indices based on single character were lower than selection index comprising a combination of two or more characters. Inclusion of characters one by one in the function resulted in the increased efficiency of selection.
Among the characters studied number of pods per plant had contributed maximum extent (9.7%) towards yield than other characters studied which was followed by days to 50% flowering and plant height (Table 2).Grain yield with other character combinations were studied for relative efficiency over grain yield pep plant. Character number of pods per plant contributed maximum efficiency than other characters in yield improvement. The relative efficiency is increases with addition of one by one yield component characters to yield (Table 2).
A function involving characters like yield, number of secondary branches per plant, number of pods per plant and test weight recorded higher relative efficiency than yield and most appropriate combination in terms of relative efficiency than other combinations. Hence, the index of these characters might be useful for simultaneous improvement of these characters. This is in accordance with the findings of [6], that the discriminate function might be useful for simultaneous improvement of character.
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