Yield and Protein Responses to Nitrogen Fertilizer of Two Winter Wheat Varieties Differing in Inherent Protein Content of Their Grain¹

Abstract

Genes that increase the grain protein potential of wheat (Triticum aestivum L.) are known. The interaction of such genes with factors of the production environment, particularly soil nitrogen availability, determines their probable value and contribution to higher protein content in wheat. Two hard winter wheat varieties differing inherently in the protein content of their grain were grown in replicated plots at selected sites in Nebraska over a 3‐year period. Nitrogen fertilizer was applied at five rates in the 1st year and at seven rates in the 2nd and 3rd years. Data were recorded for yield, test weight, and protein content of the grain. Significant protein responses to nitrogen fertilizer occurred in all trials. Responses of both varieties were linear and positive. C.I.14016 maintained a protein advantage of 2 percentage points over ‘Lancer’ at all levels of fertilizer. The protein advantage of C.I.14016 over Lancer was independent of the relative yields of the two varieties. The feasibility of effectively increasing the grain protein content of wheat by breeding is indicated by the data. Statistically significant yield responses to fertilizer were recorded in 6 of 10 trials. Yield responses of both varieties were nonlinear with the second‐degree polynomial providing a good fit of the data. Less nitrogen fertilizer was required for maximum yield of Lancer, the lower protein variety, than for C.I.14016. Test weight responses of the varieties to fertilizer were negative and linear. The test weight of Lancer was higher than C.I.14016 at all fertilizer rates.

Causes of negative correlations between grain yield and grain protein concentration in common wheat

“…LUSH (1948) and LERNER (1950) have discussed that, if genetic correlations are caused by pleiotropy, it is very unlikely that new combination traits can be obtained through deliberate hybridization and selection . Progress made to date in an attempt to simultaneously improve the GY and GPC of some wheat cultivars (MIDDLETON et al ., 1954 ;STUBER et al ., 1962 ;JOHNSON et al ., 1973) indicated that both traits could be improved by selection, and therefore, they may not be controlled by pleiotropy . Further support to the conclusion that the inverse protein-yield relationships were not caused by genetic factors can be obtained by collating the results of several studies that focused on the inheritance of GY and GPC in wheat .…”

Association between Grain Size and Shape and Quality Traits, and Path Analysis of Thousand Grain Weight in Iranian Bread Wheat Landraces from Different Geographic Regions

“…In more study, grain quality traits such as GPC in wheat have negatively correlated with grain yield and any genetic improvement in GPC has been restricted by the negative correlation between productivity and GPC (Kamra 1971;Bhatia 1975;Loffler and Busch, 1982;Blanco et al, 2012). Although grain yield and GPC are often negatively associated, some researchers reported wheat cultivars with high grain yield and high GPC in bread and durum wheat (Stuber et al, 1962;Johnson et al, 1973;Sears, 1998;De Ambrogio and Ranieri, 2002;Oury et al, 2003;De Ambrogio and Ranieri, 2002;Clarke et al, 2005). The primitive wheat species exhibit broad variation in grain size and shape, and quality in contrast to modern wheat varieties, meaning that the modern breeding germplasm has lost grain morphology and quality variation, probably due to selection for more uniform grain shape and a certain quality in the elite varieties (Gegas et al, 2010).…”

Factors affecting genotypic and environmental variance for crude protein content in cereals

“…In another study with two wheat varieties tested at 10 sites JOHNSON et al (1973) found no significant variety-nitrogen interaction for crude protein content.…”