16. Inheritance of leaf aroma in rice

J. P. SINGH and S. C. MANI

Dept. of Plant Breeding, G. B. Pant University of Agriculture and Technology, Pantnagar, Distt. Nainital, 263145 U.P., India

Inheritance of aroma in the rice leaves was studied in parental, F1 and F2 populations of two crosses: Govind/Basmati 370 and Govind/Tilakchandan. While Basmati 370 is known internationally for its quality, Tilakchandan is a local variety of Terai region of Western Uttar Pradesh. The kernels of Tilakchandan are short and scented with very good elongation capacity (> 3.0 times). Govind is a non-scented semi-dwarf variety. The presence or absence of the aroma in the top 2 leaves was recorded on individual plant basis just before flowering by the method suggested by Sood and Siddiq (1978), on 12 F1 and 300 F2 plants in each cross along with 12 plants of the parents.

The leaves were cut into small pieces and taken into glass petri-plates. About 1O ml of 1.7% potassium hydroxide (KOH) solution was added to each of the petri-plates containing the sample and covered immediately. The petri-plates were left under room temperature for 10 minutes and then opened one by one. The contents in each petri-plate were smelt. The plants possessing scent were found to produce a sharp and readily identifiable smell characteristic to scented basmati rices.

The F1 plants in both the crosses were scented. The data recorded on the presence or absence of aroma in the F2 generation and the probabilities of the genetic ratios are given in Table 1. All the 300 F2 plants could be grouped into 138 scented : 162 non-scented in the cross Govind/Basmati 370 and 139 scented: 161 non-scented in the cross Govind/Tilakchandan. This segregation fitted to a trigenic ratio of 27 scented : 37 non-scented indicating the presence of three dominant complementary genes simultaneously governing the expression of scent in Basmati 370 and Tilakchandan varieties.

Table 1. Segregation for aroma in rice leaves
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                   Parent/F1        F2 population   Probability
                               ______________________
Cultivar/Cross     character   Scented No scent Ratio  Of X2  
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Govind             Non-scented
Basmati 370          Scented
Tilakchandan         Scented
Govind/Basmati 370   Scented     138    162    27:37  0.25-0.50
Govind/Tilakchandan  Scented     139    161    27:37  0.25-0.50
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Reference

Sood, B. C. and E. A. Siddiq, 1978. A rapid technique for scent determination in rice. Indian J. Genet. Plant Breed. 38: 268-271.