Studies on graft compatibility of wild eggplant rootstocks and its evaluation under drought strees
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Date
2022-11-30
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Vasantrao Naik Marathwada Krishi Vidyapeeth, Parbhani
Abstract
The present investigation on “Studies on graft compatibility of wild eggplant rootstocks and its evaluation under drought stress” was carried out at School of Water Stress Management, ICAR-National Institute of Abiotic Stress Management, Malegaon, Baramati during kharif season in year 2021. The study was aimed to evaluate the performance of different wild species as rootstocks for cultivated eggplant under drought conditions. The five species Solanum gilo (SGI), Solanum insanum (SIN), Solanum macrocarpon (SMA), Solanum sisymbriifolium (SSI), Solanum torvum (STO) were used as rootstocks and non-grafted eggplant as a check.
The different morphological parameters of wild species rootstocks and scion were recorded with respect to its germination, days to attain grafting stage, height and girth of the seedlings at grafting stage, graft success percent, fresh and dry biomass of grafted seedlings and graft establishment. Significant differences were noted for these traits. It was found that for SGI took minimum days (4.75) for germination, whereas maximum days (17) was recorded for STO with significant different among the rootstocks. Further, rootstocks STO took minimum days (18.75) to reach grafting stage from the germination whereas, maximum days (41.75) was noted in SIN. In post-grafting parameters significant difference for graft success was noticed through the splice grafting method. In which highest graft success and compatibility was exhibited in SM/SIN recorded highest (98%) graft success followed by SM/SSI (96.00%), SM/STO (87.75%) whereas least was noted in in SM/SMA (85.00%). After grafting the significant differences were also found for seedling root fresh and dry biomass.
In post-grafting and transplanting stage all the graft combinations had 100% establishment, except SM/SMA (87.50%). The grafted plants were transplanted in pots under greenhouse conditions and were allowed to establish for thirty-five days before imposing of water stress. Then, in control conditions pot were irrigated at 80 % of field capacity whereas in drought water was withheld for 20 days. The various morphometric parameters recorded in the grafted plants under well-watered (control) and drought conditions displayed the significant differences. The plant height under stress conditions was highest in SM/SGI whereas stem girth was maximum in SM/STO among the grafted plants. After completion of experiment the plants were uprooted carefully to study the shoot and root biomass allocation in the grafted plants. The eggplant grafted onto S. torvum (36.05mg) and S. gilo (35.53mg) rootstocks were able to maintain a high shoot dry weight after 20 DAS as compared to other graft combinations. Further, the most important trait under drought stress is root length and biomass. The highest root length and biomass was obtained in SM/SSI and SM/STO under 20 DAS of withholding of irrigation water. SM/STO (8.32gm) recorded highest root dry biomass, followed by non-grafted SM (6.87gm), SM/SSI (6.57gm) while SM/SGI(3.41gm) recorded least root dry biomass. The increase root biomass under drought condition helps plant to cope stress by enhancing it root growth, it was observed that the eggplant grafted on Solanum sisymbriifolium and Solanum torvum had higher root to shoot ratio.
The significant differences were noted for physiological traits in grafted plants under drought conditions. The photosystem II efficiency indicates the status of plant health under stress conditions. It was highest in graft combinations S. sisymbriifolium (0.75) and S. torvum (0.73) even at peak stress period (20DAS). Further, these rootstocks grafted plants maintained cooler canopy, higher greenness (NDVI), RWC and chlorophyll content after 20 days of withholding of irrigation water as compared other rootstocks and non-grafted plants. Therefore, from the present study it is clearly evident that S. sisymbriifolium is outperforming rootstock followed by S. torvum among tested species. Therefore, the graft combination SM/SSI and SM/STO can be considered suitable for sustainable cultivation of eggplant crop in drought prone regions.