Title page for ETD etd-10092002-124728


Document Type Doctoral Thesis
Author Metho, Lewis Amollo
Email lewis.metho@dae.kzntl.gov.za
URN etd-10092002-124728
Document Title Yield and quality response of four wheat cultivars to soil fertility, photoperiod and temperature
Degree PhD
Department Plant Production and Soil Science
Supervisor
Advisor Name Title
Prof P S Hammes
Keywords
  • grain protein content
  • bread-making quality
  • yield components
  • wheat yield
  • photoperiod
  • soil fertility
Date 1999-07-30
Availability unrestricted
Abstract
The effects of soil nutrient status on the performance of four South African wheat genotypes were investigated in a long-term fertilization experiment. The objective was to quantify the effects of soil fertility on yield, yield components, grain nitrogen content, grain protein yield, grain protein content, flour yield and bread-making quality. The relative contribution of main stems and tillers, as well as the contribution of first, second and third kernels in the spikelets to grain yield and grain protein content were determined. The interactive effects between photoperiod, temperature and vernalization on grain yield, yield components and grain protein content were also quantified. Increasing soil fertility increased grain yield and most components of yield, grain nitrogen content, grain protein yield, aboveground biomass and harvest index, but depressed mean kernel mass. Significant interactions between cultivar and soil fertility were observed for grain yield, grain number, kernel mass, protein yield, biomass and harvest index, indicating differences in cultivar ability to produce yield and quality.

Within a cultivar, the main stem, first tiller and second tiller did not differ in mean grain protein content, indicating that late-maturing tillers do not affect the grain protein content of wheat.

Grain protein content, flour yield, loaf volume, water absorption and mixograph peak mixing time varied with soil fertility. The interaction between cultivar and soil fertility was significant for the above mentioned parameters with the exception of mixograph peak mixing time, indicating wheat genotypes differences in bread-making quality potential. The potential ability of wheat cultivar Kariega to produce higher grain yield, protein yield and loaf volume in the K and P limiting soil fertility situations deserve further investigation.

In a growth chamber study, the low temperature regimes and long photoperiod conditions resulted in the highest grain yield, number of grains, largest mean kernel size and highest grain protein content.

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  00front.pdf 144.87 Kb 00:00:40 00:00:20 00:00:18 00:00:09 < 00:00:01
  01chapter1.pdf 156.23 Kb 00:00:43 00:00:22 00:00:19 00:00:09 < 00:00:01
  02chapter2.pdf 259.43 Kb 00:01:12 00:00:37 00:00:32 00:00:16 00:00:01
  03chapter3.pdf 251.16 Kb 00:01:09 00:00:35 00:00:31 00:00:15 00:00:01
  04chapter4.pdf 186.03 Kb 00:00:51 00:00:26 00:00:23 00:00:11 < 00:00:01
  05chapter5.pdf 294.44 Kb 00:01:21 00:00:42 00:00:36 00:00:18 00:00:01
  06chapter6.pdf 249.60 Kb 00:01:09 00:00:35 00:00:31 00:00:15 00:00:01
  07chapter7.pdf 274.23 Kb 00:01:16 00:00:39 00:00:34 00:00:17 00:00:01
  08chapter8.pdf 137.25 Kb 00:00:38 00:00:19 00:00:17 00:00:08 < 00:00:01
  09resume.pdf 57.66 Kb 00:00:16 00:00:08 00:00:07 00:00:03 < 00:00:01
  10appendix.pdf 193.33 Kb 00:00:53 00:00:27 00:00:24 00:00:12 00:00:01

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