Combined Influence of Grafting and Type of Protected Environment Structure on Agronomic and Physiological Traits of Single- and Cluster-Fruit-Bearing Cucumber Hybrids

Pratapsingh Suresh Khapte,Nav Raten Panwar,Praveen Kumar,Pradeep Kumar,Uday Burman,Youssef Rouphael

doi:10.3390/agronomy11081604

Abstract

Protected vegetable cultivation is a fast-growing sector in which grafting plays a crucial role for success. Cucumber is predominantly grown under protected conditions. The popular slicing (mini) cucumber comprises two segments, single- and cluster-fruit-bearing. In the present study, the performance of select fruit-bearing hybrids grafted as scions onto commercial Cucurbita hybrid rootstock ‘NS-55’ was evaluated under three different low-cost protected structures in arid regions. With respect to type of protected structure, cucumber performance was superior under a naturally ventilated polyhouse (NVP) than an insect net house (INH) or a shade net house (SNH). Micro-climate parameters inside NVP (air temperature, RH and PAR) were more congenial for cucumber than those in net houses, thereby facilitating improved physiology (chlorophyll fluorescence, chlorophyll and plant water potential) and leaf mineral status. Grafting invariably improved growth and yield parameters under all protected structures. Overall plant performance was better in the grafted cluster-fruit-bearing hybrid ‘Terminator’ than the single-fruit-bearing hybrid ‘Nefer’ or their non-grafted counterparts. Furthermore, NVP was found to be superior to net houses for water productivity, and grafted plants were more water use efficient than their counterpart non-grafted plants. Thus, NVP can be considered a suitable low-cost protected structure in conjunction with grafting to boost cucumber crop and water productivity in arid regions.

Highlights

IntroductionMicro-climate parameters inside naturally ventilated polyhouse (NVP) (air temperature, relative humidity (RH) and photosynthetically active radiation (PAR)) were more congenial for cucumber than those in net houses, thereby facilitating improved physiology (chlorophyll fluorescence, chlorophyll and plant water potential) and leaf mineral status
Average day temperature as well as relative humidity (RH) under protected structures covered with plastic, such as naturally ventilated polyhouses (NVP), was higher than those covered with either shade nets or insect-proof nets
Photosynthetically active radiation (PAR) values were moderate in the insect-proof net house (IPN) and NVP, while the values in the shade net house (SNH) were lower throughout the cropping period

Summary

Introduction

Micro-climate parameters inside NVP (air temperature, RH and PAR) were more congenial for cucumber than those in net houses, thereby facilitating improved physiology (chlorophyll fluorescence, chlorophyll and plant water potential) and leaf mineral status. NVP can be considered a suitable low-cost protected structure in conjunction with grafting to boost cucumber crop and water productivity in arid regions. Micro-climate modification inside low-cost protected structures such as naturally ventilated plastic house (polyhouse), walk in tunnel or net houses (insect or shade net) can vary as they are often affected by outside environments [2]. The light transmission properties of the cover material affect the air temperature and humidity inside protected structures, which in turn influences the respirational demand of the crops, can alter water productivity.

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Conclusion