Grafting onto an Appropriate Rootstock Reduces the Impact on Yield and Quality of Controlled Deficit Irrigated Pepper Crops

Abstract

In this study, hybrid pepper rootstock NIBER® is tested for its ability to overcome water stress situations under soil conditions. The impact of deficit irrigation (DI) on yield and fruit quality, irrigation water use efficiency is evaluated, and consequently, the agronomic impact of employing water-stress tolerant rootstock is compared to ungrafted pepper plants. For this purpose, plants of the California-type sweet pepper ‘Maestral F1’ grafted onto NIBER® underwent a sustained DI regime during seasons 2018 and 2019 and were compared to their respective controls. Plants were drip-fertirrigated, and volumetric soil water content was continuously monitored by capacitance sensors. Gas exchange and leaf water potential measurements were taken early in the morning and midday 58, 79, and 114 days after transplanting. Plant and fruit dry biomass, marketable quality, blossom-end rot incidence and harvest index were also determined. For consecutive years, our results confirmed that grafting a pepper cultivar onto an appropriate rootstock (NIBER® in this case) as part of a DI strategy can overcome the negative effects of sustained water stress conditions. The plant biomass production and fruit yields of grafted plants were less affected by DI due to less sensitivity to water stress. This can be attributed to a less marked reduction in shoot dry weight in the grafted plants, which allowed greater whole photosynthesis by maintaining sink activity compared to ungrafted plants.

Improving Bell Pepper Crop Performance and Fruit Quality under Suboptimal Calcium Conditions by Grafting onto Tolerant Rootstocks

“…Regarding the agronomical parameters studied herein, we have demonstrated that NIBER ® (N) rootstock, previously classified as tolerant to salt and water stresses [19,24], improved commercial production, as well as reduced the non-commercial production when compared to self-grafted (V/V) or V/A6 and V/A8 plants under sub-optimal Ca concentration (SCC) (Figure 1). It is a positive effect of N rootstock given that a low Ca concentration could have resulted in an increase of BER [25,26].…”

“…Additionally, plants grafted onto N rootstock also reached the highest biomass, a symptom of its high vigour (Figure 2A) in OCC and SCC conditions. Our previous results [19,24] using N as rootstock have demonstrated a higher root length under control and abiotic stress indicating that this rootstock could help absorb a larger amount of water and nutrients. Similar studies have also demonstrated that grafting improves production under low nutrient availability, such as in the case of [27], where authors demonstrated that grafting cotton onto a tolerant rootstock improved HI, biomass and K + uptake under low K + concentration.…”

“…Afterwards, both were dried in an oven at 65 • C and weighed when weight was constant to obtain the dry weight (DW). With both measurements, harvest index (HI) was calculated by the ratio between the total dry fruit weight/total aerial dry weight [19].…”

“…Unsurprisingly, among Solanaceae, sweet bell pepper grafting has received less attention, probably due to its limited compatibility with other species [18] which limits the availability of commercial rootstocks. However, specific pepper rootstocks are an effective solution, especially against the onset of water, heat, and salt stress [8,19,20].…”

Grafting enhances plants drought resistance: Current understanding, mechanisms, and future perspectives

“…Previous studies found that some drought-resistant pepper, watermelon, and tomato rootstocks could alleviate the negative effects on roots and improve their water use efficiency to increase yields under limited irrigation conditions ( Poudyal et al., 2017 ; Al-Harbi et al., 2018 ; Yavuz et al., 2020 ). Thus, the less the reduction of photosynthetic ability, the higher the yield in grafted vegetables ( López-Marín et al., 2017 ; Gisbert-Mullor et al., 2020 ).…”