Physiological N response of field-grown maize hybrids (Zea mays L.) with divergent yield potential and grain protein concentration

Abstract

Fertilizer N availability impacts photosynthesis and crop performance, although cause-effect relationships are not well established, especially for field-grown plants. Our objective was to determine the relationship between N supply and photosynthetic capacity estimated by leaf area index (LAI) and single leaf photosynthesis using genetically diverse fieldgrown maize (Zea mays L.) hybrids. We compared a high yield potential commercial hybrid (FR1064 x LH185) and an experimental hybrid (FR1064 x IHP) with low yield potential but exceptionally high grain protein concentration. Plant biomass and physiological traits were measured at tassel emergence (VT) and at the grain milk stage (R3) to assess the effects of N supply on photosynthetic source capacity and N uptake, and grain yield and grain N were measured at maturity. Grain yield of FR1064 x LH185 was much greater than FR1064 x IHP even though plant biomass and LAI were larger for FR1064 x IHP, and single leaf photosynthesis was similar for both hybrids. Although photosynthetic capacity was not related to hybrid differences in productivity, increasing N supply led to proportional increases in grain yield, plant biomass, LAI, photosynthesis, and Rubisco and PEP carboxylase activities for both hybrids. Thus, a positive relationship between photosynthetic capacity and yield was revealed by hybrid response to N supply, and the relationship was similar for hybrids with a marked difference in yield potential. For both hybrids the N response of single leaf CER and initial Rubisco activity was negative when expressed per unit of leaf N. In contrast, PEP carboxylase activity per unit leaf N increased in response to N availability, indicating that PEP carboxylase served as a reservoir for excess N accumulation in field-grown maize leaves. The correlation between CER and initial Rubisco activity was highly significant when expressed on a leaf area or a total leaf basis. The results suggest that regardless of genotypic yield potential, maize CER, and potentially grain yield, could be improved by increasing the partitioning of N into Rubisco.

Evaluation of Australian wheat genotypes for response to variable nitrogen application

“…There was a strong correlation between NUE and NUE-PY (r = 0.79, Table 4), suggesting that NUE-PY may be considered as a component of NUE in plant breeding. The effects of NUE on both grain quantity and quality characteristics need to be considered (Peterson et al 1992;Uribelarrea et al 2009). Some genotypes which responded strongly to N fertilisation, were low yielding and had low NUE at low N supply (for example, Kord CL Plus at PIN 10, Axe at CUM 11, Grenade at ROS 11).…”

Phenology and thermal indices of maize (Zea mays L.) influenced by subsoil compaction and nitrogen fertilization under semi-arid irrigated conditions

“…Nitrogen is most yield limiting nutrient, its stress reduces grain yield by delaying plant growth and development. Maize is usually considered to have a high soil fertility requirement to achieve maximum yield (Uribelarrea et al, 2009). Thus, it require large quantities of N for optimal growth and yield.…”

Corn (<i>Zea Mays</i> L.) Plant Characteristics and Grain Yield Response to N Fertilization Programs in No-Tillage System

“…Numerous studies have reported positive effects of N fertilization on corn plant biomass, photosynthesis and grain yield (Fabrizzi et al, 2005;Ma et al, 2005;Uribelarrea et al, 2009).…”