Low temperature tolerance at early growth stage of maize hybrids released in the 1970s–2000s

Abstract

Early freezes in the spring are becoming increasingly common. To protect farmers from low temperatures (LT), crops need improved LT tolerance. The hypothesis of this paper is that maize (Zea mays L.) hybrids released in the 2000s had higher LT tolerances than those released in the 1970s. In the study, eight popular maize released between 1970 and 2010 were subjected to LT in four different trials. Germination time, growth uniformity, recovery ability from LT stress, and leaf productivity at seedling stage are important indicators in evaluating LT tolerance of maize. Hybrids released in the 1970s had a higher gibberellin A3 (GA3) content in seeds, which resulted in faster germination in LT (P = .02). In contrast, plant growth uniformity of the 2000s hybrids were higher than that of the 1970s hybrids in LT (P = .00 at emergence). Upon being returned to warm temperatures, the 2000s hybrids recovered more rapidly than old ones mainly because of the larger root systems, higher GA3, and indole‐3‐acetic acid (IAA) content in seedlings. In addition, the 2000s hybrids had a higher chlorophyll content, Fv/Fm, soluble sugar and starch content, and antioxidant enzyme activity in seedlings than old hybrids in LT, which can also contribute to a fast recovery from LT stress. Based on the growth uniformity and recovery ability from LT stress, new hybrids showed a higher LT tolerance than old hybrids during early growth stage. This study showed the genetic tolerance in LT may exist in hybrids that were released 50 yr ago, and that exporting differences between hybrids possible mechanism of temperature tolerance can be identified.

Severe storm damage and short‐term weather stresses on corn: A review

“…Cases of poor emergence arose in parts of Ohio both in 2020 and 2021 when snow fell in May on newly planted fields and led to cold water being absorbed by newly planted seeds and seedlings (Lindsey & Lindsey, 2020, 2021). Imbibitional chilling specifically has been mentioned in many extension newsletters across the United States in recent years (Karki, 2021; Licht, 2019; Lindsey & Lindsey, 2020; Lindsey & Thomison, 2016; McMechan, 2017; Miller, 2020; Nielsen, 2022), though more work examining chilling injury and damage after germination but prior to emergence is needed on current hybrids in field conditions (Xu et al., 2021). A management strategy to help minimize the effect of air temperature fluctuations on newly planted seeds could be to alter planting depth.…”

“…Afuakwa and Crookston (1984) demonstrated ear removal on the day of defoliation resulted in greater grain yield losses than allowing ears to remain attached to the plants in the field, though low‐temperature treatments were not imposed and active translocation from stalk tissue and seed metabolism may have contributed to the yield gains observed. One point to note is that all of this assessment related to yield has taken place prior to 1985, and these relationships in modern hybrids may be of value to re‐assess in future work (Xu et al., 2021). More recent work has examined the effect of killing frosts on seed quality; for ears harvested at 500–550 g·kg −1 moisture content, seed quality declines were observed in both germination and vigor assays (Aboul‐Ela, 1952; DeVries & Goggi, 2006; DeVries et al., 2007; Rossman, 1949).…”

“…Many of the studies cited in this section, while valuable, were conducted over 30 years ago in production systems that differed in their management practices (e.g., predominant tillage regime, seeding rate, planting date, rotational crops) compared to modern systems. Genetic resources have continued to change, and modern hybrids differ from hybrids used in the past studies in their phenology (dos Santos et al., 2023) and tolerance to low temperatures (Xu et al., 2021; Ying et al., 2000). Assessing how low temperatures will influence current corn production systems is essential to ensure appropriate recommendations can be made following events to improve climatic resilience.…”

Examining the Corn Seedling Emergence–Temperature Relationship for Recent Hybrids: Insights from Experimental Studies

“…A different GDD requirement for the newer hybrids compared to older hybrids could be due to genotype-environmental interactions [40]. It might be possible that newer corn hybrids have been genetically improved for other traits, such as disease resistance, drought tolerance, or yield potential, which could inadvertently affect their GDD requirements for seedling emergence [41].…”

Molecular mechanisms underlying low temperature inhibition of grain filling in maize (Zea mays L.): coordination of growth and cold responses

“…LT stress during the grain-filling period prevents the conversion from soluble sugar to starch, and hence inhibits kernel development (Jones et al, 1981). LT stress can reduce the granule size, branched chain length, and relative crystallinity of starch in maize kernels (Yang et al, 2021), which are also detected in rice (Oryza sativa L.; Arshad et al, 2017;Xu et al, 2021) and chickpea (Cicer arietinum L.; Nayyar et al, 2005). Xu et al (2021) addressed that the reduction of kernel weight was significantly related to the inhibition of starch synthesis rate at LT stress, in relation to sink activity.…”