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Polymerase chain reaction (PCR) amplifi cation with primers specifi c to the rDNA region successfully amplifi ed the 1160-bp DNA fragment from a Huanglongbing (HLB)-infected sweet orange sample with mottling symptoms leaves, but not from healthy sweet orange plants. The PCR product of 1160-bp was used as probe labeled with biotin for detection of the HLB pathogen in the nucleic acid spot hybridization (NASH) test. It was found that the HLB pathogen could be detected up to 1:100 dilution in HLB-infected tissue. Total DNA extracted from HLB-infected tissue was diluted 2-fold as 900 ng in TE buffer and spotted on a nitrocellulose membrane. Strong signals were observed up to 225 ng of DNA dilution, whereas a moderate signal was recorded at 112 ng. No hybridization signal was observed in the healthy samples, while strong signals were observed in the positive control.

Of the 242 groundnut genotypes, tested both in epiphytotic field and laboratory conditions, the genotypes viz., ICGV 90009, ICGV 86699, ICGV 86329, 91177, 91234, ICGV-94252 and TG 26 were found promising both with low incidence of PBND besides longer incubation periods, DFSA, DLSA and IP 50%. Further, significant positive correlation was found between IP 50% vs DLSA, DFSA and final PBND (%) was negatively correlated with IP 50% and DFSA.

Aflatoxin contamination of peanut caused by Aspergillus flavus, is a major problem in the rainfed agriculture in the semi-arid tropics associated with end-ofseason drought stress. The present study was taken up to investigate the relationship between total phenol content of peanut leaves and kernels with aflatoxin content. Moisture stress was imposed from 60DAS to till harvest under rainout shelters and the data was recorded at the end-ofseason drought conditions during kharif, 2003. Results revealed that, among the twenty one peanut genotypes tested, J-11, IC-48, ICGV 89104 and ICGS-76 had consistently low aflatoxin levels (<25 ppb) and high total phenols in leaves and kernels (>1,300 lg g -1 ) at harvest under end-of-season drought conditions. Aflatoxin production was negatively correlated with total phenols in kernels (r 2 = -0.42, P < 0.05) and leaves (r 2 = -0.37, P < 0.05). No consistent relationship was observed between kernel infection and aflatoxin production.