BGN 12: Coheritability estimates in barley BARLEY GENETICS NEWSLETTER, VOL. 12, II. RESEARCH NOTES
Chandra & Makde, pp. 7-11

II. 2. Coheritability estimates in barley.

Avinash Chandra and K. H. Makde, Department of Botany, Dharampeth Mahavidyalaya, Nagpur 440 010 (M.S.) India.

Barley being an important crop is widely grown from sub-arctic to tropical regions of the world. Appreciating fully its importance in Indian agriculture, considerable efforts to increase its economic production are constantly under way. Although it occupies as small percentage of the total cropped area in the country, it is next important to wheat as a winter cereal. It is the most dependable grain crop, when grown under conditions of stress and specially good for areas with low or uncertain rainfall, because of having drought resistance, salinity and alkalinity. Considering its importance being a cereal crop, the present study was undertaken to measure the coheritability estimates for response to joint inheritance for various attributes. Nei (1960) has provided information on joint inheritance for different pairs of characters.

MATERIALS AND METHODS
From a large collection of barley germplasm only twenty-five genotypes (14 Indian and 11 exotic varieties) were grown in a randomized block design having 3 replications in rabi seasons of 1976-77 and 1977-78. Adequate space, between rows and seeds in row, was maintained to identify individual plants in the field at a later stage. Timely manuring and irrigation were applied to secure good stand. One line represented one plot. The data were recorded on 10 randomly selected plants per plot, representing the varieties. The traits considered were plant height, number of internodes per main shoot, length of spike, number of effective tillers per plant, number of spikelets per spike, 250 grain weight and total grain yield. The coheritability was calculated by using covariances as below:

                             genotypic covariance
Coheritabillty =   phenotyplc covarlance    x 100
 

RESULTS AND DISCUSSION
Table l under discussion reveals that analysis of variance was significant. Differences among population in 1976-77 and 1977-78 for all the traits except number of internode per main shoot, indicates that there is much variability among the genotypes.

Table 1. Analysis of variance for 7 characters for the year 1976-77 and 1977-78.

Table 2. Coheritability estimates for 7 characters for the year 1976-77 and 1977-78.

Coheritability estimates appearing in Table 2 show that grain yield per plant with number of spikelets per spike to be highest (139.3610 for 1976-77 and 177.3506 for 1977-78), followed by that with number of internode per main shoot (113.6721 and 117.5223) as well as number of effective tillers per plant (103.3612 and 122.0068), respectively. These estimates of grain yield with remaining characters to be high estimates of the magnitude of 90% or above are deemed to be high. Hence, these traits should be given due weightage by breeder in making the selection for high yielding genotypes.

Coheritability estimates to be low in both the years of investigation for plant height association with number of internodes per main shoot. The cursory examination of the table under reference showed higher magnitude of coheritability for effective tillers per plant association with height of plant, number of internodes per main shoot, and length of spike for both years. Negative but higher estimates for number of spikelets per spike with number of internodes per main shoot to be observed. More than 100% coheritability estimates indicate that the genotypic covariances are higher than phenotypic covariances and thus these combinations are highly under genotypic control. The present study lends support to the studies of Singh and Singh (1969) in field pea and Tewari (1974) in barley. Recently, Singh (1978) reported higher yield estimates of coheritability association between number of pods per bunch and number of seeds per pod followed by days to flower and number of pods per bunch in Dolichos lablab.

Acknowledgment:
Grateful thanks are due to Principal V. B. Phatak for providing facilities.

References:
Nei, M. 1960. Studies on the application of biometrical genetics to plant breeding. Mem. Coll. Agric. Kyoto Univ. Japan:82-100.

Singh, T. P. and K. B. Singh. 1969. Interrelationship of quantative traits with grain yield in field pea. Indian J. Genet. 29:483-487.

Singh, S. P. 1978. Coheritability estimates in Dolichos lablab (L.). Sci. and Cul. 44(11):502.

Tewari, S. N. 1974. Biometrical investigation in barley. Ph.D. Thesis, Agra University, Agra, India.

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