Division of Plant Introduction, Indian Agricultural Research Institute, Delhi-12
In view of the growing importance of guar seed for its gum in the international trade, correlation studies and formulation of selection indices in relation to seed yield were undertaken.
Seventy single plant selections were grown in randomized block design replicated three times and studied during 1963 and 1964. Observations were taken on height, number of branches, number of pods, pod length, seed weight and yield. Seed weight was, however, taken only in 1963.
Estimates of correlations at genotypic, phenotypic and environmental levels were obtained between yield on one hand and its components on the other, besides the correlations amongst the yield components. Selection indices were formulated using different yield contributing components.
High positive correlations between yield on one side and branches and pod number on the other were obtained in both the seasons at genotypic as well as at phenotypic levels. Branch number also showed high positive association with yield at environmental level in the two years. Seed weight gave negative correlation with yield at all the levels.
Amongst the yield components, it was observed that height was positively correlated in both the seasons with all the characters excepting seed weight where it was negative though not significant. A significant positive association was observed between height and number of branches in both the seasons at genotypic level. Correlation of pod length was mostly negative excepting with seed weight where it was significantly positive. Thus a longer pod was associated with lesser number of branches and pods but with bold seeds. There was a high positive correlation between number of branches and total pods in both the years.
Of the selection indices evaluated, maximum efficiency was exhibited by one which included all the important components of yield, viz. height, branch number, pod number and yield itself. Number of branches and total pods when considered together gave the next highest efficiency consistently in both the seasons. Number of pods alone also showed a high efficiency in one season but not in the other.
