VARIETIES OF TOMATO FRUIT, ABUNDANCE AND MOLECULAR BIODIVERSITY OF ALTERNARIA ALTERNATA (L) TOMATO FRUIT CANKER, FROM FARMERS FIELD IN NIGER STATE, NIGERIA

Abstract

ABSTRACT Tomato (Solanumlycopersicum L) is an important vegetaive crop worldwide. However, the quality of fruit production is hindered by fruit canker caused by Alternaria alterrnata. Thereforethis research investigated the biodiversity of Alternaria alternata from farmers’ tomato fieldsin Niger state. Three hundred samples of Tomato fruit with canker samples were collected from thirty (30) farms across all the three Agricultural Zones of Niger State, namely Bida, Lapai, Lemu, Kataeragi and Sabon-gida (zone 1), Garatu, Sabon-dag and Paiko (zone 2), Wushishi and Zungeru (zone 3). Isolation of fungal species was done using dilution of 104factor on PDA. Identification of tomato varieties were done following standard procedures. Molecular diversity were examined using Internal Transcribed Spacer (ITS) marker. Two hundred (200) isolates were obtained. The order of occurrence of highest to least was as follows. Samples from Bida (17.5 %) has the highest occurrence of canker followed by samples from Lemu (14 %) whiles samples from Garatu (5 %) were the least with occurrence of fruit canker.Varietal results shows that Ronita V.F (29.5 %) has the highest followed by Roma V.F (22 %) whiles variety Chico (9 %) recorded the least incidence of Alternariaalternata across selected study areas.The blast results obtained from this study showed that samples from Bida (OK175632), Lapai (OK175633), Sabon gida (OK175635) Kataeregi (OK175636) from Zone I. Garatu (OK175637), Paiko (OK175639) from Zone II. Wushsishi (OK175640) from Zone III, all had 100% presences of Alternaria alternata, while Lemu (OK175634) from Zone I and Sabon daga (OK175638) from Zone II, are 99.80%. Dendogram obtained from the molecular analysis grouped the fungal strains in to two (2) major clusters. Alternaria alterrnatawere abundant in all the three zones under the study. Morphological and molecular studies showed that all the isolates were Alternaria alterrnata but of different strains. The biodiversity analysis shows that different strains of Alternaria alternata werepresent and responsible for tomato fruit canker in Niger state. Therefore, research on control of Alternaria species should be intensified to proffer solution to reduce economic loses.