Eslabones: características, certificaciones, tendencias y espacios de innovación

Introduction

Grape is a popular fruit crop in temperate regions. Its cultivation is ex-panding rapidly in the tropics and subtropics. It is grown for the juicy edible berries. Fruits are tasty and nourishing, containing high carbohydrates and minerals such as magnesium, potassium, phosphorus, and vitamins B₁and B₂. Grape is easily digestible because it contains high amounts of glucose and fructose. It is also used in the preparation of juice, wine, syrup, and rai-sins.

Origin and Distribution

Grape has its origin in Central Asia, particularly in Armenia, and wild relatives are grown in areas between the Black and Caspian Seas. Grape is predominantly cultivated in Afghanistan, Australia, Canada, England, France, Germany, India, Israel, Italy, the Philippines, Portugal, Russia, Spain, and the United States.

Morphology

Grape belongs to family Vitaceae and has somatic chromosome number 2n = 38. It is a dicotyledonous, deciduous, and woody climbing vine.

Leaves are broad and cordate, with three to five lobes and intermittent ten-drils. Flowers are borne in panicle formation and are mostly perfect. Fruit cluster is variable in size, form, and color; the fruit skin adheres to the pulp.

Seeds are brown, none to four in number, and pear-shaped.

Seed Storage

Grape is propagated by cuttings, and seldom by seeds. However, seeds are used in evolving new cultivars through hybridization and in long-term conservation of genetic diversity through seed storage. Grape seeds show

orthodox storage behavior, where drying or exposure to chilling tempera-tures does not kill seeds. Fresh seeds exhibit dormancy, which is beneficial for better seed storage.

Seed Collections

Grape is a cool-season crop. It grows well in temperate regions, except in areas of extreme cold. It needs warm growing conditions during fruit devel-opment and ripening. Rooted cuttings are used for grape propagation. Vines are suitably trained on arches, trellises, or poles (see Figure 5.1). Flowering occurs on new growth. Fruits are nonclimatric; therefore, ripe bunches are plucked for seed purposes. Berries are crushed without injuring the seeds.

Seeds are separated from the pulp, washed in water, dried, and packed ac-cording to storage requirements.

Fruit maturity. Seeds from mature berries emerge sooner and produce more plantlets of higher dry weight than seeds from green berries. Grape berries harvested at the green and mature stages and stored in paper bags at 20°C for 12 months showed seed germination percentage of 14.5 and 73.5, respectively (Maeda, Pereira, and Terra, 1984).

Seed Germination

Freshly extracted seeds normally contain a high proportion of dormant seeds. Scott and Ink (1950) reported that fresh seeds had low germinability and low seedling vigor. Plants were dwarfs when such seeds were sown.

FIGURE 5.1. Grapevine with Ripe Berries

Seeds obtained from self-pollination are lower in viability than seeds from open pollination (Mamarov, Ivanov, and Katherov, 1958). Similarly, seeds obtained from grafted plants showed higher viability than seeds from self-rooted plants (Ivanov, 1961). Harmon and Weinberger (1959) noted that stratification or moist ripening results in higher seed germination. Grape seeds stored at 4 to 5°C for 60 days showed improved percentage of germi-nation and early emergence (Forlani and Coppola, 1977), while Eris (1976) recommends storage for 120 days. Seed germination can also be hastened by keeping seeds in a peat-sand (1:1) mixture in polyethylene bags at 0 to 2°C (Misic, Lekic, and Todorovic, 1978). In another study, temperature re-gime (0 to 10°C) and storage duration (up to five months) increased germi-nation. The most effective temperature for higher germination (40 percent) was 0°C. The effect decreased progressively with higher temperatures, and only 5 percent germinated at 10°C (Balthazard, 1974). However, a longer period of stratification at 1 to 3°C for 180 to 210 days improved germination (Dolgova, 1959). These seedlings grew vigorously and showed improved winterhardiness. Selim and colleagues (1981) reported that warm stratifica-tion (18°C for 30 or 60 days) followed by cold stratificastratifica-tion (5°C for 30 days) gave higher germination and a higher number of normal seedlings.

The improvement was attributed to an increase in endogenous level of gibberellic acid (GA)-like substances. Furthermore, gibberellic acid treat-ment replaces the chilling or light requiretreat-ment for germination (Pereira and Maeda, 1986). A long prechilling treatment is rarely successful in promot-ing germination of dormant seeds. Gibberellins are more effective in pro-moting germination of dormant seeds than other growth substances (Kachru, Singh, and Yadav, 1972). Chohan and Dhillon (1976) reported that auxin activity increases with longer stratification. Although no gibberellin activ-ity occurs in fresh seeds, it is higher in extracts of moist seeds stratified for 60 days. Abscisic acid-like inhibitor content is initially higher but is re-duced on stratification. In many grape varieties, seeds are empty and do not germinate in spite of moist ripening or gibberellin applications (Chadha and Randhawa, 1967).

Heat treatment. Grape seed coat is hard and takes longer to imbibe. Im-mersing seeds in hot water (27 to 54°C) for 24 h also does not break the dor-mancy (Manivel and Weaver, 1974).

Light. Seed exposure to continuous light promotes the germination pro-cess. Pereira and Maeda (1986) reported that seeds of cv. Patricia germi-nated well in continuous light for 48 h but failed in dark conditions.

Storage Conditions

Grape seeds are short-lived under ambient conditions. Seeds deteriorate at higher temperature and relative humidity. Dolgova (1959) noted poor

germination of seeds when stored in dry conditions for six to eight months.

Viability is preserved when seeds are stored in the berry itself or stratified in damp sand at 1 to 3°C for 180 to 210 days. Seed drying after harvest and/or stratification at 18.3 to 21.1°C reduces germination slightly, and even more through drying without subsequent stratification. Dry seeds stored at 4.4°C for three months showed higher germination than those stored at room tem-peratures (Singh, 1961). Seeds stored in paper or polyethylene bags at 20°C germinated poorly, unlike those stored at 2°C in polyethylene bags (Eynard, Gay, and Savino, 1972). Furthermore, fresh seeds stored in glass jars or pa-per bags remained viable at 10°C, and dry seeds, at 20°C (Maeda, Pereira, and Terra, 1985). Seeds stored in polyethylene bags at 5 and –18°C for two years resulted in 45 and 41 percent germination, respectively, after gibberellic acid (2000 ppm) applications (Doijode, 1993). Viability (67 percent) was extended further, for five years, by packing seeds in polyethylene bags and storing at 5°C (Doijode, unpublished data).

REFERENCES

Balthazard, J. 1974. The effect of temperature on true and apparent dormancy in grape vine seeds. Comptes Rendus Hebdomadaires des Seances del Acad. des Sci. D. 278:2143-2144.

Chadha, K.L. and Randhawa, G.S. 1967. Studies on grape seed germination: A re-view. Indian J. Hort. 24:181-187.

Chohan, G.S. and Dhillon, B.S. 1976. Seed dormancy and endogenous growth sub-stances in Anab-e-Shahi grapes. Vitis 15:5-10.

Doijode, S.D. 1993. Storage of grape seeds and improvement of their germinability with certain chemical treatments. J. Mah. Agril. Universities 18:107-109.

Dolgova, A.E. 1959. The effect of storage conditions of grape seeds on germination and growth of the seedlings. Sad i Ogorod No. 9:65-68.

Eris, A. 1976. On the influence of growth regulators and stratification on germina-tion of seeds of the vine cv. Muscat Hamburg. Mitteilungen Rebe Wein Obstbau Fruchteverwertung 26:85-90.

Eynard, I., Gay, G., and Savino, P.G. 1972. Studies on the germinability of grape vine seeds as affected by the method of storage, physical and chemical seed treatment and ambient conditions during germination. Ann.della Facolta di Sci.

Agranedella University degli Stud di Torina 8:127-156.

Forlani, M. and Coppola, V. 1977. The effects of cold storage, gibberellic acid, and temperature on the germination of Vitis vinifera seeds. Revista di Viticoltura di Enologia 30:445-451.

Harmon, F.N. and Weinberger, J.H. 1959. Effect of storage and stratification on germination of Vinifera grape seeds. Proc. Am. Soc. Hort. Sci. 73:147-150.

Ivanov, I.K. 1961. Characteristics of seeds and seedlings obtained from self rooted and grafted grape vines. Agrobiologija 6:814-820.

Kachru, R.B., Singh, R.N., and Yadav, I.S. 1972. Physiological studies on dor-mancy in grape seeds (Vitis vinifera). II. On the effect of exogenous application

of growth substances, low chilling temperature and subjection of the seed to run-ning water. Vitis 11:289-295.

Maeda, J.A., Pereira, M.De.F.D.A., and Terra, M.M. 1984. Effect of the fruit devel-opmental stage on seed quality of the grape vine cultivar Patricia. Bragantia 43:659-666.

Maeda, J.A., Pereira, M.De.F.D.A., and Terra, M.M. 1985. Storage conditions and grape vine seed viability and dormancy. Bragantia 44:245-254.

Mamarov, P., Ivanov, J., and Katherov, K. 1958. Effect of presowing treatments of vine seeds on germination. Sborn CSI Akad. Zemed Ved Rostt Vyroba 31:1211-1216.

Manivel, L. and Weaver, R.J. 1974. Effect of growth regulators and heat treatment on germination of Tokay grape seeds. Vitis 12:286-290.

Misic, P., Lekic, N., and Todorovic, R. 1978. Studies on methods for improving seed germination in grape vine. Savremena Poljoprivreda 26:77-80.

Pereira, M.De.F.D.A. and Maeda, J.A. 1986. Environmental and endogenous con-trol of germination of Vitis vinifera seeds. Seed Sci. Technol. 14:227-235.

Scott, D.H. and Ink, D.P. 1950. Grape seed germination experiments. Proc. Am.

Soc. Hort. Sci. 56:134-139.

Selim, H.H., Ibrahim, F.A., Fayek, M.A.E.L., El-Dean, S.A.S., and Gamel, N.M.

1981. Effect of different treatments on germination of Romi Red grape seeds.

Vitis 20:115-121.

Singh, S.N. 1961. Germination of grape hybrid seeds by chilling. Curr. Sci. 30:62.

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