Phytohormone dynamics during embryogeny and embryo desiccation in the recalcitrant seeds of Vateria indica L
Israel Journal of Plant Sciences, 2022
Vateria indica L. is an endemic arborescent recalcitrant tree species, native to the South-Wester... more Vateria indica L. is an endemic arborescent recalcitrant tree species, native to the South-Western-Ghats of India. The natural regeneration process of the species is hindered by many factors including seed recalcitrance. Recently the species has been categorised as vulnerable since the population is fragmented and rapidly declining. Seed development is a highly complicated process which involves the interaction between phytohormones which regulate the process at different stages of morphogenesis. The orthodox seed development is marked by three distinct stages such as histodifferentiation, reserve accumulation and drying but in recalcitrant seeds, drying phase is absent. Recalcitrant seeds show marked differences from orthodox seeds in development. The onset of different stages is marked by a definite peaking and lowering of phytohormones and the hormonal pattern varies in orthodox and recalcitrant seeds. The present study was conducted to understand the interplay of phytohormones d...
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Papers by Ajay Kumar
focused on the population abundance of sucking insect pests (whiteflies and aphids) affecting urd bean and their correlation with weather parameters. In the experiment, the initial occurrence of the aphid
population was recorded during the 28th SMW, while whiteflies were first noted during the 30th SMW. Both insect populations reached their peak levels during the 36th SMW. Correlation studies were performed using the Karl Pearson coefficient formula.
resulting in substantial yield and economic losses. To address this menace, an exploration of intrinsic
resistance within pea germplasm becomes imperative for effective disease management. In our study,
phenotyping of 1095 pea accessions, sourced from both indigenous and exotic origins, under natural
epiphytotic conditions during Rabi 2021-22, revealed a prevailing susceptibility, with over 60 per cent
disease severity in majority of accessions. Remarkably, only 22 accessions, including IC208327, IC220109,
IC220378, IC258401, IC262762, IC262849, IC267140, IC267174, IC267727, IC274039, IC274040,
IC310074, IC311066, IC345548, IC424898, IC552779, IC613133, IC629544, IC629687, NC57793,
IC220193 and EC598669, exhibited resistance with a disease score of <1. Subsequent, pot screening of
these 22 resistant accessions under artificial epiphytotic conditions during Rabi 2022-23 confirmed their
resistance showing disease severity ranging from 5.83 - 17.50 per cent. Recognizing the pivotal role of
resistant varieties in disease management, these identified accessions hold immense potential as resistant
donors in crop improvement programs.
inoculation with Bipolaris sorokiniana, on important wheat seed quality of popular cultivar (cv.) DBW 187, was estimated in
comparison to susceptible check WH 147. DBW 187 responded very effectively against pathogen keeping all parameters well
ahead of susceptible check. The variety could resist declination in per cent germination with 8.07% in comparison to WH 147
which resulted in 14.72% reduction in germination after pathogen inoculation. Similarly, after pathogen’s inoculation, speed
of germination (80.06) and vigour index I (2677) and II (24379) were significantly higher in cv. DBW 187 as against cv. WH
147, which resulted in lower speed of germination and vigour index I and II, i.e. 74.37, 2249, and 16715, respectively. Amongst
the biocontrol agents, Trichoderma harzianum was found to be the most effective in managing this pathogen, which caused
86.30% inhibition in mycelial growth of B. sorokiniana. Amongst the seven fungicides used to manage Bipolaris sorokiniana
in vitro, tebuconazole 50% + trifloxystrobin 25% WG, propiconazole 25% EC both at 75 and 100 ppm, and kresoxim methyl
44.3% SC at 100 ppm were most effective against Bipolaris sorokiniana, causing complete inhibition in its radial growth. Conclusively,
wheat cv. DBW 187 has capacity to resist seed health deterioration caused by the pathogen. Out of seven evaluated
fungicides, the best three newer fungicide molecules, viz., tebuconazole 50% + trifloxystrobin 25% WG, propiconazole 25% EC,
and kresoxim methyl 44.3% SC, can judiciously be utilized in combination with biocontrol agents, Trichoderma harzianum, T.
asperellum, and Chaetomium globosum, keeping the fungicide load minimum for the effective management of B. sorokiniana.
Keywords Bipolaris sorokiniana · Fungicides · Disease management · Seed quality · Spot blotch · Wheat
Keywords: Alternaria brassicae, botanicals, fungicides, leaf blight, mustard.
of diterpene glycoside, respectively.