Abstract
SUMMARY In wheat, the photothermal quotient ( Q , the ratio between mean incident solar radiation and mean temperature is greater than 4·5°C in the 30 days preceding anthesis), is a good estimator of grain number/m 2 (GN) and of yield. Previous investigations have not analysed in depth whether the responses of GN to Q differ between wheat cultivars, or what is the cause of the eventual variation. In the present work, the results of field experiments carried out between 1994 and 2001 in various locations were used to test the following hypotheses: (i) the responses of GN to Q differ between wheat cultivars; (ii) these differences are caused by differences in the spike fertility index (GN/g spike dry weight/m 2 at the beginning of grain filling (SDW)). The responses of GN to Q were compared for five wheat cultivars (four bread wheats and one durum wheat) and it was found that with Q values above 0·3 MJ/m 2 /d°C, all responses of GN to Q were linear, positive and parallel. A method was then proposed to obtain cultivar-specific GN from a common relationship between GN and Q . This method would facilitate GN estimation in crops with changes in sowing dates, sites or years, starting from data of potential GN and yield that is relatively easy to obtain. Differences among cultivars in response to Q were due to differences in GN response at SDW. Similar SDW values produced different GN, depending on the spike fertility index of each cultivar. The cultivars did not differ in their responses of SDW to Q . The association between spike fertility index and SDW was strongly negative in bread wheat. At lower levels of Q or SDW, the spike fertility index increased in all cultivars, at least when changes in SDW or Q were caused mainly by intercepted solar radiation, but the present results demonstrate that differences between cultivars also exist in this relationship.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 8
Claim · model-written summary
Above the specified Q threshold, all cultivar grain-number responses to Q were linear, positive and parallel.
- Taxon
- wheat
Triticum aestivumt0 - Outcome
- responses of GN to Qe0
- Direction
- positivee0
- Setting
- Q values above 0·3 MJ/m 2 /d°Ce0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“with Q values above 0·3 MJ/m 2 /d°C, all responses of GN to Q were linear, positive and parallel”
t0“Cultivar effects on relationship between grain number and photothermal quotient or spike dry weight in wheat”
Claim · model-written summary
A common GN–Q relationship was proposed to obtain cultivar-specific grain numbers.
- Taxon
- wheatTriticum aestivumt0
- Outcome
- cultivar-specific GNe0
- Comparator
- common relationship between GN and Qe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A method was then proposed to obtain cultivar-specific GN from a common relationship between GN and Q”
t0“Cultivar effects on relationship between grain number and photothermal quotient or spike dry weight in wheat”
Claim · model-written summary
Cultivar differences in response to Q arose from differences in grain-number response at spike dry weight.
- Taxon
- wheatTriticum aestivumt0
- Outcome
- Differences among cultivars in response to Qe0
- Qualifier
- differences in GN response at SDWe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Differences among cultivars in response to Q were due to differences in GN response at SDW”
t0“Cultivar effects on relationship between grain number and photothermal quotient or spike dry weight in wheat”
Claim · model-written summary
Similar spike dry weights produced different grain numbers depending on each cultivar’s spike fertility index.
- Taxon
- wheatTriticum aestivumt0
- Material
- each cultivare0
- Outcome
- different GNe0
- Qualifier
- spike fertility indexe0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Similar SDW values produced different GN, depending on the spike fertility index of each cultivar”
t0“Cultivar effects on relationship between grain number and photothermal quotient or spike dry weight in wheat”
Claim · model-written summary
Cultivars did not differ in their spike dry weight responses to Q.
- Taxon
- wheatTriticum aestivumt0
- Material
- cultivarse0
- Outcome
- responses of SDW to Qe0
- Direction
- did not differe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The cultivars did not differ in their responses of SDW to Q”
t0“Cultivar effects on relationship between grain number and photothermal quotient or spike dry weight in wheat”
Claim · model-written summary
Spike fertility index and spike dry weight were strongly negatively associated in bread wheat.
- Taxon
- wheatTriticum aestivume0
- Material
- bread wheate0
- Outcome
- association between spike fertility index and SDWe0
- Direction
- negativee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The association between spike fertility index and SDW was strongly negative in bread wheat”
Claim · model-written summary
Spike fertility index increased at lower Q or spike dry weight in all cultivars when intercepted radiation was the main driver.
- Taxon
- wheatTriticum aestivumt0
- Material
- all cultivarse0
- Outcome
- spike fertility indexe0
- Direction
- increasede0
- Qualifier
- at least when changes in SDW or Q were caused mainly by intercepted solar radiatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At lower levels of Q or SDW, the spike fertility index increased in all cultivars, at least when changes in SDW or Q were caused mainly by intercepted solar radiation”
t0“Cultivar effects on relationship between grain number and photothermal quotient or spike dry weight in wheat”
Claim · model-written summary
Cultivars differed in the relationship between spike fertility index and Q or spike dry weight.
- Taxon
- wheatTriticum aestivumt0
- Outcome
- differences between cultivars also exist in this relationshipe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the present results demonstrate that differences between cultivars also exist in this relationship”
t0“Cultivar effects on relationship between grain number and photothermal quotient or spike dry weight in wheat”