scholarly journals Plant Growth Regulators and Yields of Seed Potatoes

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 853F-853
Author(s):  
Manjula S. Bandara ◽  
Karen K. Tanino ◽  
Doug R. Waterer
Keyword(s):  
Plant Growth ◽  
Plant Growth Regulators ◽  
Growth Regulators ◽  
Seed Tuber ◽  
Russet Burbank ◽  
Field Conditions ◽  
Tuber Initiation ◽  
Growth Stages ◽  
Tuber Production ◽  
Cut Seed

Seed potato growers seek to maximize yields of desirable sized tubers. This study examined how foliar applications of plant growth regulators influence yields of drop or single-cut seed tubers under field conditions. In 1993, paclobutrazol (PTZ; 300, 450, and 600 mg·liter–1), kinetin (KIN; 10 and 20 mg·liter–1), and methyl jasmonate (MJ; 10–7, 10–6, 10–5, and 10–4 M) were applied to `Norland' (NOR) and `Russet Burbank' (RB) potatoes. In 1994, PTZ (300 mg·liter–1), KIN (both rates), and MJ (10–7 and 10–6 M) treatments were eliminated, and GA3 at 250 mg·liter–1 or KIN at 20 mg·liter–1 was applied to some of PTZ treatments. In 1994, the cultivar Shepody (SH) also was included. Plants were treated at two growth stages; NOR (1993), RB (1993 and 1994), and SH (1994) were treated when tubers were <10 mm or <20 mm in diameter. NOR (1994) was treated at stolon initiation (no tubers) or early tuber initiation (<8 mm in diameter). PTZ had no effect on seed tuber (25–50 mm in diameter) yield in NOR in either season. PTZ increased seed tuber number (STN) in RB by 29% to 40% and in SH by 57% to 70% over the controls. KIN had no effect on STN in any cultivar. MJ had no effect on STN in NOR (1993) or in RB in either season or in SH in 1994. In 1994, the highest rate of MJ (10–4 M) increased STN in NOR by 40% over the controls. GA3 had no beneficial effect on STN when applied after PTZ. This study suggests that, under field conditions, PTZ can increase seed tuber production in RB and SH while MJ was effective in NOR potatoes.

Effects of plant growth regulators on stem extension and yield components of linseed (Linum usitatissimum)

1999 ◽  
Vol 132 (2) ◽  
pp. 189-199 ◽  
Author(s):  
M. H. LEITCH ◽  
O. KURT
Keyword(s):  
Plant Growth ◽  
Plant Growth Regulators ◽  
Seed Yield ◽  
Growth Regulators ◽  
Field Experiments ◽  
Stem Length ◽  
Growth Stages ◽  
Early Application ◽  
Number Of Stems ◽  
Total Oil

The response of linseed to treatment with two plant growth regulators (PGRs), chlormequat and ethephon, applied at a range of growth stages (corresponding to average mainstem lengths of 10, 23, 46, 55 and 64 cm) and in various combinations (single and repeated applications of chlormequat and ethephon, either alone or mixed) was studied in field experiments over two seasons in 1992 and 1993 at the University College of Wales, Aberystwyth. Reduction in mainstem length was dependent upon the type of PGR and the timing of its application. Chlormequat alone was consistently more effective than ethephon alone, while a mixture of the two at half rates was similar to chlormequat alone. The largest reductions in mainstem length (16·6% with chlormequat and 6·1% with ethephon, averaged over the two years) were achieved when the PGRs were applied when mainstems averaged 22–23 cm in length. Response to PGRs became progressively smaller with later applications. However, the reduction in mainstem length, when expressed as a percentage of that part of the stem yet to extend (i.e. final untreated stem length−stem length at the time of PGR application), was shown to be remarkably consistent across all (apart from the first) timings of application, with average values of 28·4 and 7·4% for chlormequat and ethephon respectively.Application of both PGRs increased tillering and increased significantly the number of stems per unit area at maturity. This response occurred irrespective of timing of application and was greater following treatment with ethephon than with chlormequat. In the first year, the effects of PGRs on dry matter production and seed yield were small and not statistically significant. In the second year, significant reductions in seed yield were associated with those PGR treatments which promoted tillering most, i.e. early application of ethephon. Smaller yields were the result of fewer capsules per plant. Furthermore, a significant correlation between mainstem length and the number of seeds per capsule indicated a reduction of 0·78 seeds per capsule for every 10 cm reduction in stem length. While total oil content of seed remained unaffected by PGR applications, treatments which included chlormequat at an early growth stage (either alone or in combination with ethephon) altered the relative proportions of fatty acids, reducing the content of linolenic acid while increasing that of oleic acid.

Recent developments in growth regulators for cereal crops

1981 ◽  
Vol 10 (8) ◽  
pp. 371-378 ◽  
Author(s):  
J J Batch
Keyword(s):  
Plant Growth ◽  
Plant Growth Regulators ◽  
Growth Regulators ◽  
Crop Management ◽  
Cereal Crops ◽  
Growth Stages ◽  
Arable Crops ◽  
Grain Formation ◽  
Recent Developments ◽  
Existing Chemicals

Because of the high cost of developing and registering new agrochemicals, plant growth regulators, hitherto small speciality crop-management aids, can now only be seen to have a commercial future in the larger markets such as are provided by ‘broad-acre’ arable crops. Temperate cereals can be manipulated at various growth stages. Existing chemicals control lodging; as yet undiscovered ones may lead to advantageous distribution of nutrients in favour of grain formation.

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