Tag Archives: GDD

1630-1641 I. Dimante and Z. Gaile
Assessment of potato plant development from Minitubers
Abstract |

Assessment of potato plant development from Minitubers

I. Dimante¹²* and Z. Gaile¹

¹Latvia University of Life Sciences and Technologies, Faculty of Agriculture, Liela street 2, LV 3001, Jelgava, Latvia
²Institute of Agricultural Resources and Economics, Priekuli Research centre, Zinatnes street 2, Priekuli, LV 4126, Latvia
*Correspondence: ilze.dimante@arei.lv

Abstract:

In production of minitubers, manipulation of their weight by modifying production method is common. Under field conditions plant development from minitubers can be affected by their weight, as well as cultivar. This objective of this study was to compare plant development from four minituber weight classes (MtC) (3 to 4.99 g, 5 to 9.99 g, 10 to 19.99 g, and > 20 g) with broken apical dominance of cultivars ‘Monta’, ‘Prelma’ and ‘Mandaga’. ‘Prelma’ and ‘Mandaga’ had a similar development pattern, and minitubers > 20 g required significantly less growing degree days (GDD) to emerge than minitubers from the lightest classes. The heaviest minitubers needed on average 176 GDD for 50% emergence and 207 GDD were needed for the lightest class. The difference in GDD between the marginal MtC was more pronounced in period between 50 and 80% emergence. MtC did not affect the final rate of emergence. Number of above ground stems (1.4–4.0) was significantly affected by MtC. ‘Monta’ had significantly different development – delayed emergence, lower emergence rate, less above ground stems, faster canopy closure. Our study showed that plant development was significantly affected by MtC and cultivar. Differences between MtC were more pronounced under adverse meteorological conditions.

Key words:

, , , ,




229–243 G. Sidlauskas and S. Bernotas
Some factors affecting seed yield of spring oilseed rape (Brassica napus L.)
Abstract |
Full text PDF (410 KB)

Some factors affecting seed yield of spring oilseed rape (Brassica napus L.)

G. Sidlauskas¹ and S. Bernotas²

¹Lithuanian Institute of Agriculture, Akademija 5051, Dotnuva parish, Kedainiai distr., Lithuania, e-mail: gvidas@lzi.lt
²Lithuanian Institute of Agriculture Vezaiciai branch, Vezaiciai, LT-5845 Klaipeda distr., Lithuania, e-mail: filialas@vezaiciai.lzi.lt

Abstract:

The effect of nitrogen rates, time of nitrogen application, concentration of nitrogen, phosphorus and potassium in aboveground plant dry matter, stand population density, mean daily temperature, precipitation rate, growing degree days accumulated by plants at different growing stages and the duration of vegetative growth period on seed yield of Star, a cultivar of Brassica napus L., were studied in the field experiment. The seed yield was significantly affected by nitrogen rates of up to 120  kg ha-1. Further increase in nitrogen fertilisation had only a little effect on the seed yield of spring oilseed rape. There was a possibility to prolong the nitrogen application time until the start of flowering. However, in poorest soils, especially under unfavourable growing and development conditions, late nitrogen application could be much less effective. Nitrogen concentration in plant dry matter at 4–5 leaf stage, at the start and end of flowering and at the seed development stage had a significant effect on seed yield of spring oilseed rape. Phosphorus concentration was not important in the second part of vegetative growth. Potassium concentration, on the contrary, in the first part. With an increase of stand population density to up to 170 plant m-2 seed yield of spring oilseed rape was increasing. The increase in the duration of vegetative growth period and precipitation rate resulted in a higher seed yield. Meanwhile, the increase of mean daily temperatures and growing degree days had a negative effect on seed yield of spring oilseed rape. Presented regression equations could be used for a model for prognosis of seed yield of spring oilseed rape, based on agronomic and climatic factors.

Key words:

, , , , , , ,