Studies on Vegetative Propagation of Grapevine (Vitis vinifera L.)

Abstract

Experiments of this study were conducted during three consecutive years (2005, 2006 and 2007) in the orchard of the Department of Horticulture, Ministry of Agriculture, Kassala State, Kassala (Lattitude17°15N; Longitude 40°34E), Sudan. The objective of the research was to study the effect of type cutting, season of the year cuttings were collected, planting medium and growth regulators on rooting of cuttings of grapevine (Vitis vinifera L.). A tissue culture experiment was also conducted to confirm previous findings in the tissue culture laboratory concerning in vitro propagation of grapes. Four grape varieties; namely, Dr.knight, Biz-elanza, Syrian and Raziky were used as source of stem cuttings and explants for the tissue culture experiment. Preliminary experiments revealed the superiority of Biz-elanza to the other cultivars in response to the propagation operations. Unless otherwise specified, this cultivar was used throughout this study as the main source of cuttings and explants to develop an optimal method for grape propagation, which in turn, it is hoped, will be used for the propagation of other grape varieties. Two types of cuttings, basal and terminal were planted in five planting media namely; loam alone, mixture of 1 sand: 1 loam, 2 sand:1 loam, 1 sand :2 loam and sand alone; over the three seasons in each year of the study. The effects of storage of cuttings before planting and the incubation after planting on rooting were also studied. The application of IBA and NAA singly, each in two concentrations (500 mg/l-1000mg/l) and two commercial rooting hormones were tested on rooting of basal cuttings of Biz-elanza cultivar. All planted cuttings were incubated under lath house conditions except for the experiment where the effects of incubation conditions on rooting were investigated. ix A randomized complete block design was used. Each experiment was repeated three times in each season with 10 cuttings per treatment and data were recorded after 6 weeks from planting. The parameters measured were percent rooted cuttings, number of roots per cutting and length of roots. As for the tissue culture experiment the parameters measured included number of shoots, leaves and nodes and length of shoots. Basal cuttings gave higher values for rooting percentage, root number per cutting and root length than terminal cuttings in the tested planting media and across the three planting seasons. High values were however, obtained during autumn and winter compared to summer values. The soil mix 2 sand:1 loam gave significantly higher values of all parameters measured regardless of time of cutting collection during the year or cutting type. The results of the duration of storage of cuttings before planting on rooting ability of basal cuttings of Biz-elanza in three seasons showed that one week storage period was optimal for the successful propagation of grapes via rooting of stem cuttings. Neither of the two commercially formulated rooting hormones induced rooting of basal cuttings but “Radicate” consistently gave better rooting values than “K-humate”, the other commercial rooting hormone tested. Non-significant differences between 500 and 1000 mg/l IBA concentrations in rooting percentage over the three seasons were observed. However, both IBA concentrations gave significantly higher values of all measured parameters than the other treatments tested in autumn and winter whereas differences from the control were non-significant in summer. Non-significant differences in rooting percentage were also noted between the two NAA concentrations tested. Additionally, the control excelled both concentrations of this auxin in summer and was equal to them in terms of values of measured parameters in winter and autumn. x Incubation of cuttings under a polyethylene plastic tent inside a lath house gave high values for all parameters measured. However, these values varied with the planting medium used. High rooting percentage (100%) was achieved in the soil mix of 2 sand:1 loam and only 30% rooting was recorded in a mix of 1 sand:2 loam. Rooting inside the lath house without a plastic tent ranked second upon use of a mix of 2 sand :1 loam, and gave equal values with planting under a plastic tent in 1 sand:2 loam. Rooting percentage was lowest when cuttings were planted outdoor. The results of the tissue culture experiment showed the superiority of the medium developed by Osman (2004) to that developed by Idris (unpublished data). It seems that type of cutting, time of the cuttings were collected, duration of storage before planting, exogenously applied auxin and incubation conditions after planting play an important role, among other factors, in the rooting of grape stem cuttings. The use of basal cuttings collected in autumn or winter, stored for one week, treated with 1000 mg IBA/l and the incubation of planted cuttings in a lath house under a plastic tent is the recommended procedure for the successful propagation of grape cultivars. It is also possible to use the in vitro technique of stem nodal explants for the production of large numbers of plants in a short period of time.