The effect of the time and mode of application of gibberellic acid on the growth and yield of potato plants derived from true potato seed

Abstract

The effect of the time and mode of treatment (single or repeated applications) of gibberellic acid (GA 3 ) on the growth and tuberisation of plants grown from true seed (TPS) of potato Chacasina F 1 was studied. Plant height, fresh and dry weight of stems and leaf dry weight increased in response to single or repeated GA 3 applications. Leaf colour was not affected by single applications of GA 3 , whereas repeated applications caused a reduction in colour intensity. The numbers of secondary shoots and leaves per plant as well as total leaf area were largely unaffected by GA 3 , although repeated applications from early in the growth cycle increased these parameters under conditions of decreasing photoperiod. When applied as a single dose during spring, GA 3 caused an increase in the number of tubers per plant, with a concomitant decrease in tuber dry matter content, irrespective of application date. In autumn the number of tubers per plant increased following single applications of GA 3 up to 50 days after transplantation, whereas tuber dry matter decreased. By contrast, repeated applications of GA 3 in both seasons increased tuber number only when initiated early in the growth cycle. The mean weight of tubers per plant was variably affected by GA 3 application, depending on the season, time and mode of application. It is suggested that the foliar application of GA 3 to plants from TPS at an early stage of vegetative development may be of value for seed tuber or micro-tuber production, primarily by increasing the number of tubers produced per plant.

The effect of the time and mode of application of gibberellic acid and inhibitors of gibberellin biosynthesis on the dormancy of potato tubers grown from true potato seed

“…This role of gibberellin appears to be expressed through its inhibitory effect on tuberisation, since repeated applications of GA 3 starting 40 DAT significantly increased sprouting (Table 1) while at the same time reducing tuber yield. 15,16 However, exogenously supplied GA 3 may be metabolised at a different rate than gibberellins within the tubers, so the observed effects might differ from those produced by a rise in endogenous gibberellin levels.…”

“…The application of GA 3 to plants from TPS has been shown to increase leaf area mainly as a result of increased leaf size, 12 whereas GA 3 increases leaf number in plants from seed tubers. 15 Moreover, repeated applications of GA 3 to plants from TPS initiated early in the growth cycle cause an increase in tuber number per plant, 16 whereas in plants from seed tubers the tuber number per plant is decreased by repeated GA 3 applications. 15 Apart from these examples, however, GA 3 appears to affect the sprouting of tubers from TPS in a similar way to those grown from seed tubers.…”

“…GA 3 application does not constitute a danger to human health or the environment, unlike chemicals such as rindite and ethyl bromide which have been used for dormancy breakage. 25 The cost of application is relatively low and GA 3 does not affect tuber yield 16 or the subsequent growth and yield of the next generation. 26 On the other hand, inhibitors of gibberellin biosynthesis do not extend dormancy and are therefore not capable of increasing the storage life of tubers destined for consumption.…”

Mechanism of Allium Crops Bulb Enlargement in Response to Photoperiod: A Review

“…Earlier reports have revealed that the application of GA3 increased bulb weight in onion under deficit irrigation [63]. On the contrary, a few results have shown that the application of GAs caused a decline in tuber production in potato [64]; fruit production in sweet pepper [65], grape [66], and pear [67]; and root weight in carrot [59]. In potatoes, it was testified that GA3 treatment improved the number of tubers per plant [68].…”

“…In addition, it has been stated that a high concentration of GA 3 and high frequency of application GA 3 inhibit lettuce growth [60] and decrease fruit weight in plum [81]. The application of GA 3 decreased root, tuber, fruit weight, and yield in other crops as well [59,64,67]. Previous reports have revealed that the application of GA 3 had a positive and negative effect on the organ nutritive eminence of potatoes, sweet peppers, and sweet cherries [65,82,83].…”