Tomato Rootstock Breeding: Evaluation of Tomato Interspecific Hybrid Rootstocks Under Greenhouse Conditions

Abstract

Tomato grafting is an important agricultural technique to overcome biotic and abiotic stresses and increase plant growth and productivity. Breeding and selection of resistant and vigorous rootstocks are necessary to achieve grafting goals. Therefore, this study was conducted to evaluate eight tomato interspecific hybrids between accession Solanum lycopersicum L. LA1221 'VFNT cherry', as the female parent and each of wild accessions S. chmielewskii LA1028 (Chm-1028); S. galapagense LA0530 (Gal-530); S. habrochaites CGN 15391 (Habr-15391) and LA1777 (Habr-1777); S. pennellii AusTRCF 312075 (Pen-312075) and LA716 (Pen-716); and S. pimpinellifolum AusTRCF311810 (Pim-311810) and CGN18388 (Pim-18388), as male parents, as rootstocks under greenhouse conditions compared to the commercial rootstock 'Emperador', to select the most suitable rootstock. S. lycopersicum 'Santa Cruz Piedade' was selected as a scion and used as self-grafted and nongrafted controls. Plant growth and productivity measurements were estimated for the grafted and non-grafted plants. The response to the evaluated rootstocks was not consistent for many of the studied traits, denoting that the scion was differently influenced by the rootstocks. Grafts did not always outperform self-grafts. Grafting onto either Pen-312075, Habr-15391, or Pim-18388. in addition to self-grafting, increased the total and marketable yields compared to the non-grafted plants, with proportions that would enable increased profits and cover the extra cost of grafting. In addition, fruits from these grafts had acceptable quality traits. Therefore, the interspecific hybrids Pen-312075, Habr-15391, and Pim-18388 are considered suitable rootstocks to improve the scion 'Santa Cruz Piedade'. Greater and continuing efforts are needed to evaluate several interspecific hybrids, as well as different high yielding scion cultivars, to select the most suitable rootstocks for different scion cultivars.

Application of Phenomics to Elucidate the Influence of Rootstocks on Drought Response of Tomato

“…S. pimpinellifolium was one of the parents in the hybrid rootstock that also favoured the vigorous root and shoot growth in these graft combinations, as has been previously reported [55,64]. The yield advantage in grafted tomato plants has been explored from the interspecific hybrid rootstock S. lycopersicum × S. pennellii [45]. Our study suggests a more significant advantage of using the S. lycopersicum × S. pennellii cross combination in contrast to using S. pimpinellifolium as a male donor parent or their F 1 hybrid rootstocks under water stress conditions.…”

“…However, undesired traits, such as reproductive incompatibility [44], poor germination of seeds and the reduction in stem girth of plants may limit the scope of using wild species directly as rootstock. Hence, instead of simply using wild species as a rootstock, the hybrids or derivatives of wild species can be successfully used as rootstocks to obtain desired results [14,45]. Several reports suggest that droughtinduced growth inhibition in tomatoes can be circumvented by grafting [46,47].…”

Interspecific Hybrid Rootstocks Improve Productivity of Tomato Grown under High-temperature Stress

“…No significant effects of grafting on tomato fruit quality such as TSS, titratable acidity, and vitamin C compared with the nongrafted plants were observed (Jenkins et al 2022;Walubengo et al 2022). Conversely, grafting improved the fruit quality of tomato, including firmness, TSS, vitamin C, and pH, in other studies (Mahmoud 2020;Oztekin and Tuzel 2017). Furthermore, slight increases of b-carotene, total phenols, and total antioxidants were found among the grafted plants when compared with nongrafted tomato plants (Manickam et al 2021;Pugalendhi et al 2021).…”

Applying population-based threshold models to quantify and improve seed quality attributes

“…In many cases, seeded flats are placed in climate-controlled rooms so that optimal temperature and moisture conditions can be maintained during germination and emergence to increase uniformity. Even so, problems can persist, such as in coordinating the emergence of rootstock seedlings of wild species accessions for grafting with hybrid scion varieties in tomatoes (Mahmoud, 2020). Machines have been developed specifically to image young plants and sort them into trays with uniform seedlings for automated grafting (https://www .tta .eu /equipment /selecting /flexsorter).…”