INVITRO EVALUATION OF INDIGENOUS BIOAGENTS ON EGG HATCHING AND LARVAL MORTALITY OF ROOT-KNOT NEMATODE (MELOIDOGYNE INCOGNITA) INFECTING MULBERRY

In vitro studies were conducted to evaluate the efficacy culture filtrate of different concentrations (25, 50, 75 and 100%) of the indigenous bioagents viz. Trichoderma viride. Pseudomonas fluorescens, Trichoderma harzianum, Aspergillus niger, Pochonia chlamydosporia and Fusarium ax-ysporum on egg hatching and larval mortality of root knot nematode, Meloidogyne incognita at three exposure periods. All the indigenous bioagents had significantly suppressed egg hatching and viability of freshly hatched second stage juveniles of the nematode. However, at all concentrations of the indigenous bioagents tested, T viride was superior over other five bioagents tested in inhibition of egg hatching (61-68.74 per cent) and larval mortality (30-75.33 per cent)

MANAGEMENT OF ROOT- KNOT NEMATODE (MELOIDOGYNE INCOGNITA) INFECTING MULBERRY

viride, 2x10“cfu/g) and commercial bioagents (Trichoderma viride, 2x10"cfu/g) and Psuedomonas fluorescens, 1x10fcfu/g) under field conditions. All the bioagents tested were effective in suppressing nematode population and improving plant growth and yield. However, higher shoot length (125.10cm), number of leaves (156.00) and leaf yield (3.57kg) were recorded in indigenous Tviride (a) 30g/m followed by indigenous T viride @ 20g/m, Pseudomonas fluorescens (commercial) and T viride (commercial) (d) 20g m. respectively. Lowest nematode population in soil (162.00) and root (25.33) were recorded in indigenous T. viride (a 30g/m treated plot followed by indigenous T viride @ 20g/m. Maximum reduction of galls (49.33) and egg masses (7.50) per five gram of root was recorded in indigenous T viride (a 30gsm compared to other treatments

Exploring Key Blast and Bacterial Blight Resistance Genes in Genetically Diverse Rice Accessions through Molecular and Phenotypic Evaluation

Blast and bacterial blight (BB) are the most dangerous rice (Oryza sativa\ua0L.) diseases that limit rice production significantly.\ua0Pib,\ua0Piz‐t, and\ua0Pi9\ua0are reported as key resistance genes for blast whereas\ua0Xa21,\ua0Xa4,\ua0Xa7, and\ua0xa13\ua0are considered as important resistance genes for BB. Using gene‐specific DNA markers, the presence of these resistance genes was screened in 211 diverse rice accessions originating from 26 countries. In molecular marker analyses, specific amplification patterns for the\ua0Pib\ua0and\ua0Piz‐t\ua0resistance alleles were observed in 56 and 23 accessions, respectively, whereas the\ua0Pi9\ua0resistance allele was not observed at all in these accessions. For BB, at least one BB resistance gene was present in 148 of the 211 evaluated accessions. All 211 accessions were evaluated for blast resistance using natural isolates and for BB resistance using Race 4 (PX071) and Race 6 (PX099). Among 211 accessions, 89 exhibited hypersensitive blast resistance reactions, whereas 85 and 37 accessions were rated as resistant or moderately resistance to BB Races 4 and 6, respectively. The combined analysis of molecular and phenotypic reactions (marker‐trait association assay) revealed that landraces possessed rare and several desirable genes compared with breeding lines with a narrow genetic base, hence these landraces serve as the valuable source for exploring new resistance genes for crop improvement. An interesting similarity in gene distribution pattern was observed in\ua0Pib\ua0with\ua0Xa21\ua0and in\ua0Piz‐t\ua0with\ua0Xa7. The analyzed blast and BB resistance genes were in a range of combinations in different landraces and breeding lines, which can be used in gene introgression and pyramiding programs as alternative resistance sources