**2.1 M2 generation**

#### **2.1.1 Chlorophyll mutations**

The chlorophyll mutants were scored from 7 to 10 days after sowing. The different types of chlorophyll mutants such as albina, xantha, chlorina and viridis were reported in all mutagenic treatments.

Amongst all the treatments used gamma radiations had induced the highest chlorophyll mutation frequency, followed by combination treatments. Prakash and Halaswamy, (2006) and Manigopa-Chakraborty *et al*., (2005) and Bolbhat and Dhumal (2009) have also reported induction of chlorophyll mutation in horsegram with GR and their combination.

The frequency of total chlorophyll mutants varied for single as well as combination of gamma radiation and EMS. In gamma radiation the average percentage of chlorophyll mutation frequency was 1.47% which was slightly higher than combination treatments (1.23%). The highest chlorophyll mutation frequency was recorded in 200Gy (1.70%). The values of chlorophyll mutation frequency were ranging from 1.09% to1.70%. Amongst all types of chlorophyll mutations, albina and chlorina types showed higher percentage (0.64 and 0.58%). The percentage of xantha and viridis was 0.41 and 0.28 respectively. The average number of chlorophyll mutations was 24.25, while the average frequency was 1.47%.

The combination treatments showed wide range of total percentage of chlorophyll mutations. The range varied from 0.74% to 1.72%. Highest chlorophyll mutation frequency (1.72%) was noted in 100Gy + 0.3%EMS.

Reddy and Annadurai (1992) claimed that chlorophyll mutation can be used as an index for evaluating the mutagenic action of different mutagens. It is also important for assessing the potency of mutagen and also can be used as an indicator of factor mutations. Chlorophyll mutations are used as a dependable index for evaluating the genetic effects of mutagens.

Albina, xantha, chlorina and viridis were found to be the most abundant type of chlorophyll mutants induced by GR and combination treatments in horsegram Bolbhat and Dhumal (2009). Manjaya *et al*., (2007) and Tambe *et al*., (2010) attributed this genes concerned with the development and expression of chlorophyll pigments.
