Ten varieties of groundnut were screened to know their resistance/susceptibility against bruchid,
C.
serratus up to 4 months of storage. However, there was a wide variation in adult emergence, pod damage and weight loss present in different varieties. The findings are presented hereunder.
Adult emergence
The results presented in Table 1 clearly showed that there were significant differences in per cent adult emerged from the pods of different groundnut varieties. The adult emergence after 60 days ranged between 46.82 to 82.39 per cent. Among varieties, GJG-9 recorded the lowest per cent adult emergence (46.82%) followed by GG-HPS-2 (50.35%), GJG-33 (53.08%) and GG-38 (55.42%). Among varieties, GJG-32 (82.39%) recorded the highest adult emergence followed by GJG-22 (75.32%). The adult emerged after 90 days ranged from 52.35 to 86.84 per cent. The variety GJG-9 recorded lowest per cent adult emergence (52.35%) and the variety GJG-32 recorded the maximum adult emergence (86.84%). However, the varieties like GJG-31 and GG-20 recorded a moderate adult emergence
i.
e., 65.34 and 74.82 per cent, respectively. There were significant difference in the adult emerged after 120 days from the pods of different groundnut varieties. The adult emergence ranged between 55.35 to 91.81 per cent. The groundnut variety, GJG-9 recorded lowest per cent adult emergence (55.35%) and the variety GJG-32 recorded the maximum per cent adult emergence (91.81%). The number of groundnut bruchid adult emergence varied in different groundnut varieties
(Harish et al., 2012). The present results are also in conformity with the results of
Bhoraniya (2011) who reported that the per cent adult emergence from different groundnut varieties ranged from 80.00 to 100.00 per cent. Similarly, the reports of
Ramadevi et al., (2014), Nadaf (2008) and
Rekha et al., (2017) also revealed the differential response of adult emergence by bruchid in different varieties of groundnut.
Per cent pod damage
The data on the per cent pod damage after 60 days in each repetition of different varieties together with the total number of pods observed, healthy and damaged pods were counted. The data in Table 1 showed that maximum and minimum infestation of 2.90 to 23.61 per cent occurred in varieties GJG-9 and GJG-32, respectively. A significantly minimum
i.
e., 2.90 per cent pod damage was found in variety like GJG-9 was significantly maximum pod damage was noticed in varieties GJG-32 (23.61%). The data on the per cent pod damage after 90 days showed that maximum and minimum pod damage of 6.23 to 29.36 per cent occurred in variety GJG-9 and GJG-32, respectively (Table 1). A significantly minimum 6.23 per cent pod damage was noticed in variety GJG-9 whereas significantly maximum per cent pod damage was recorded in varieties like GJG-32 (29.36%) followed by GJG-22 (25.32%). The data on the pod damage after 120 days showed that the maximum and minimum infestation was ranging between 9.62 to 34.24 per cent in varieties GJG-9 and GJG-32, respectively. A significantly minimum 9.62 per cent pod damage was recorded in variety GJG-9 while significantly maximum pod damage was recorded in variety GJG-32 (34.24%). In a study
Ramadevi (1996) observed up to 20 per cent of pod damage by this pest.
Najitha et al., (2013) studied the damage potential of groundnut bruchid and recorded pod damage up to 84.46 per cent in groundnut variety Kadiri 1641.
Harish et al., (2012) noted the maximum pod damage
i.
e., 80.7 per cent was recorded in GG-20. Thus, in the present investigation similar trends were observed and was closely support the present findings.
Weight loss
The results on weight loss after 60 days presented in Table 1 depicted that maximum and minimum weight loss of 21.90 and 3.23 per cent occurred in varieties GJG-32 and GJG-9, respectively. A significantly minimum 3.23 per cent weight loss was recorded in variety GJG-9 and was followed by GG-HPS-2 (4.78%). Further, significantly maximum weight loss (21.90%) was recorded in variety GJG-32. The weight loss after 90 days showed that significantly minimum 8.14 per cent weight loss was recorded in variety GJG-9 and it was followed by GG-HPS-2 (9.98%). Further, significantly higher weight loss was observed in varieties GJG-32 (29.67%). Further, weight loss after 120 daysshowed that maximum and minimum weight loss of 37.89 and 10.11 per cent occurred in varieties GJG-32 and GJG-9, respectively. A significantly minimum 10.11 per cent weight loss was recorded in varieties GJG-9 and followed by GG-HPS-2 (14.10%). Moreover, significantly higher
i.
e., 37.89 per cent weight loss was recorded in varieties GJG-32.
Behera et al., (2017) reported that per cent weight loss due to groundnut bruchid infestation was varied from 1.2 to 17.8 per cent in first month of storage.
Najitha et al., (2013) studied the damage potential of groundnut bruchid and recorded 19.5 and 21.14 per cent weight loss in Kadiri 008 Bold and Kadiri 1641 groundnut varieties, respectively. In the present study, more or less similar trends were observed and closely supported the present findings.
Grouping of the groundnut varieties against bruchid
An attempt was made to categorize different groundnut varieties into three categories of susceptibility to bruchid,
C.
serratus viz., least susceptible, moderately susceptible and highly susceptible as per
Shivalingaswamy and Balasubramaniam (1992). The details of categorization are presented in Table 2. Based on the per cent adults emerged after 120 days of the storage period, the varieties GJG-9 and GG-HPS-2 found least susceptible varieties which recorded less than 61.11 per cent adults emerged. The varieties
viz., GJG-31, GJG-33, GG-20, GG-35, GG-38 and TG-37-A were found moderately susceptible which recorded 61.11 to 85.19 per cent adults emerged. However, the varieties GJG-22 and GJG-32 found highly susceptible varieties which recorded more than 85.19 per cent adults emerged. Based on the per cent pod damage after 120 days of the storage period, the data presented in Table 2 showed that the varieties GJG-9 and GG-HPS-2 found the least susceptible, which recorded less than 13.37 per cent damage. The varieties
viz., GJG-31, GJG-33, GG-20, GG-35, GG-38 and TG-37-A were found moderately susceptible which recorded 13.37 to 29.93 per cent damage. However, the varieties GJG-22 and GJG-32 found highly susceptible varieties which recorded more than 29.93 per cent damage. On the basis of per cent weight loss after 120 days of the storage period, the data presented in Table 2 showed that the varieties GJG-9 and GG-HPS-2 found the least susceptible varieties which recorded less than 14.62 per cent loss. The varieties
viz., GJG-31, GJG-33, GG-20, GG-35, GG-38 and TG-37-A were found moderately susceptible which recorded 14.62 to 33.00 per cent loss. However, the varieties GJG-22 and GJG-32 found highly susceptible varieties which recorded more than 33.00 per cent loss. Overall, it was concluded that the varieties GJG-9 and GG-HPS-2 fall under the least susceptible category of all the parameters and can be considered as least susceptible to
C.
serratus. The varieties GJG-22 and GJG-32 fall under the highly susceptible category of all parameters and can be considered as highly susceptible to
C.
serratus. These findings are in agreement with the findings of
Radadia (2003) who screened 22 different groundnut cultivars and reported that cultivars GG-2 and GAUG-10 had the highest infestation of
C.
serratus. Bhoraniya (2011) screened groundnut cultivars against
C.
serratus in terms of oviposition, larval period, pupal period, total development period, survival percentage and growth index and found GG 13 and GG 11 were resistant whereas, GG 2 was susceptible. Moreover,
Harish et al., (2012) observed that the number of eggs and adults of
C.
serratus that emerged in groundnut were highest in GG 20 and also revealed that genotypes with large seed sizes as more susceptible to bruchid infestation. The present findings are more or less in accordance with the findings of earlier workers.
