PINCHING AS A FACTOR INFLUENCING THE COMPONENTS OF GROWTH, DEVELOPMENT, AND PRODUCTIVITY OF THE SUGAR BEET SEED BEARERS

Authors

  • O. V. Balahura Institute of Bioenergy Crops and Sugar Beet of NAAS of Ukraine , Інститут біоенергетичних культур і цукрових буряків НААН України

DOI:

https://doi.org/10.31548/dopovidi2016.05.017

Keywords:

pinching, components of cross growth and development, productivity of seed bearers

Abstract

A characteristic biological feature of sugar beet seed bearers is the uneven development of both individual plants and plants in agrocoenosis in general, in particular, crossed components of CMS hybrids. This leads to the uneven flowering of the crossed components resulting in lower yield and number of seeds. Therefore, diminishing the differences in the development of seed plants is a relevant issue. One of the measures to affect growth and development of seed bearers is pinching. The purpose of pinching is to limit unproductive growth processes. A number of researchers carried out experiments on sugar beet seed bearers’ formation by pinching. They found that pinching seed bearers positively influenced the processes of shaping the growth and development of seed bearers and improves productivity.

In 2004-2006, in RF Shevchenkivske we studied the specifics of seed formation in sugar beet hybrid Ukrainian CMS 70 as affected by pinching. The treatments were as follows: (i) treatment without pinching (control); (i) complete pinching; (ii) pinching only CMS component; (iii) pinching only pollinators. Pinching seed bearers (3-5 cm) is carried out manually during the mass stem development (height of seed bearers of 40-50 cm).

It was found out that pinching limits stem the growth of seed bearers; meanwhile, shoots of the first and the second orders grew more intensively.  Slowing down of the growth occurs within 5 days after pinching. Thus, if suppose height increment of seed bearers being 100% than the increment of the main stem (pinched) on average over three years, on the 5th day was 27%, 10th ˗ 46%, 20th ˗ 70%, and 30th  ˗ 77% of the control. The height of the seed bearers before harvesting, in the control treatment, was 149-166 cm and in treatment with pinching, 134-150 cm. The number of branches of the first order as a result of pinching increased from 35-39 to 45-48, and of the second 51-52 to 61- 66.

Monitoring of the development stages of Ukrainian CMS 70 sugar beet hybrid’s components showed that in all the years of research, plants of pollinator grew more intensively, regardless pinching. For example, in 2004 (in control treatment), on May 15, 26% of CMS plants and 32% of pollinator plants entered the stem formation stage and on May 27, 84 and 98%, respectively. On June 15, the flowering stage was noted in 29% CMS and 36% pollinator plants and on June 26 76% and 80%, respectively. And as of July 24, the percentage of ripened seed bearers was 84% in CMS and 96% in pollinator.

In the complete pinching treatment, the development stages of seed bearers occurred more intensively. To illustrate, in the control treatment, on May 15, 26% of CMS plants and 32% pollinator plants entered the stem formation stage, while in pinching treatment 30 and 36%, respectively. The percentage of plants in the flowering stage as of June 15 was 29% in CMS and 36% in pollinator plants in the control treatment and as of June 26, 80 and 76%, 81 and 88%, respectively.

The above patterns of the hybrid components were more distinct when only CMS plants were pinched. For example, in 2004, as of May 15, 24% of CMS and 59% of pollinator plants entered the stem formation stage. To compare, in the control treatment without pinching, these figures were 26% and 32%, respectively. The flowering stage as of June 15 was observed in 24% of CMS and 67% of pollinator plants and as of June 26, 81% and 98%, respectively. In comparison, in the control treatment as of June 15, the percentage of CMS plants in the flowering stage was almost the same as in the treatment with pinching (29 and 24%), while in the seed bearers of pollinator it was 36 and 67%, respectively, and as of June 26, 76 and 80% ,81 and 98%, respectively.

Somewhat other patterns were observed when only pollinator plants underwent pinching. Thus, the stage of flowering as of June 15 was marked in 37% of CMS and 41% of pollinator plants and as of June 26, in 81 and 83%, respectively. The percentage of plants in the stage of ripening in this treatment, as of July 24, was 86% in CMS and 92% in pollinator, while in the control the control 84 and 96%, respectively.

Dynamics of the flowering of the Ukrainian CMS 70 components showed that in the plants subjected to pinching it occurred 5-7 days later, but it occurred more intensively. For example, in 2006, in the control treatment as of June, 30% of CMS and 40% of pollinator plants were in the stage of flowering. In the middle of the flowering stage, this difference increased, but the end of the stage flowering occurred more synchronously. As of July 12, 78% of CMS and 85% of pollinator plants flowered. The difference in the flowering of CMS and pollinator plants was stronger when only CMS plants were pinched. As of June 18, flowering occurred in 38% of CMS and 65% of pollinator plants. This difference persisted almost to the end of flowering.

When pinching only pollinator plants, flowering in CMS and pollinator plants occurred evenly, and almost simultaneously at the end of the flowering stage. As of June 18, 38% of CMS and 40% of pollinator plants were in flowering stage and as of July 12, 80 and 81%, respectively, in the control treatment. Pinching of only pollinator seed bearers proved to be more effective.

 These patterns of growth and development of the Ukrainian CMS 70 hybrid components when applying techniques limiting non-growth processes positively influenced their seed productivity. On average over three years, seed yield in treatments with pinching was 0.41-0.58 t/ha higher than in the control.

Analysis of the fraction composition of seeds as affected by pinching allowed to identify some patterns: first, in all the treatments with pinching the number of fruit of small size (3.0-3.5 mm) and large (> 5 mm) decreased; secondly, the number of fruit of the major factions used for seeding (3.5-4.5 and 4.5-5.5 mm) increased.

1. Growth and development of the Ukrainian 70 CMS hybrid components occurred somewhat not simultaneously and flowering was not synchronous. In all the years of the experiment, plants of the pollinator developed more intensively and usually they entered flowering stage first.

2. One of the most effective ways of forming highly productive sugar beet seed bearers is pinching, that is a technique that limits the main stem growth and stimulates development of branches of the first, the second and the third order.

3. Development stages of two hybrid components after pinching occur 3-5 days later, however, they long less (i.e. good and even) when compared with non-pinched seed bearers. However, in this case, again pollinator plants developed more intensively than CMS plants. This pattern was even stronger when only the plants of CMS component underwent pinching. When pinched only pollinator plants, development of both components occurred more evenly and flowering almost simultaneously.

4. Pinching of the pollinator contributed to increased seed yield and quality. When growing seeds of Ukrainian CMS 70 hybrid, pinching of pollinator proved to be more efficient as compared with pinching both components and, especially, only CMS component.

5. Efficiency of pinching depends on the weather conditions of a certain growing season. Under favourable conditions (HTC 2.0-1.7) the efficiency rises due to better regrowth of shoots, but in adverse environment (HTC 1.2-0.7) reduces. 

References

Balan V. M. (1965). Chekanka vyisadkov odnosemyannoy saharnoy sveklyi [Pinching of the monogerm sugar beet seed bearers]. In Tezisyi dokladov nauchno-proizvodstvennoy konferentsii molodyih uchenyih [Abstracts of the scientific conference of young researchers]. Sugar Beet Institute, 114-118.

Levchenko A. I. Improvement of measures on influencing growth of the direc-sownt sugar beet seed bearers to increase their seed productivity. MUA, Kyiv,20. [in Ukrainian]

Yukhnovskyi O. I. (2003). Biologichni osoblyvosti ta produktyvnist komponentiv shreschuvannia ChS gibrydiv, zalezhno vid umov vyroschuvannia [Biological features and components of productivity of the components of CMS hybrids]. In Zbirnyk naukovykh Pratz ITzBNAAN, 5, 128-133. [in Ukrainian]

Published

2016-09-14

Issue

Section

Agronomy