Cold Test Germination Research Articles

Challenges in sunflower breeding for cold tolerance

Introduction. Sunflower is grown as an oilseed crop worldwide. For sunflower production, it is vital to have cold-tolerant hybrids. An appropriate method to assess cold tolerance is a prerequisite for successful breeding of cold-tolerant sunflower.
 Purpose and Objectives. To evaluate cold tolerance of sunflower in the laboratory and its tolerance in the field, to identify promising combinations, to assess the capacity of a laboratory test to predict tolerance of sunflower in the field and to verify relationships of cold tolerance with ripeness group and yield.
 Materials and Methods. Sunflower was grown in compliance with standard farming techniques. In total, 192 F1 hybrids were obtained. The lines and hybrids were screened for ability to germinate at above-zero low temperature by laboratory test. The field tolerance at the initial stages of plant growth was determined with a 9-point scale. Relationships between the investigated parameters were analyzed by linear regression.
 Results and Discussion. The highest field tolerance at the initial stages of plant growth was recorded for Kh4713V, Skh777А and Skh808А lines. However, they only conferred tolerance to some of their hybrids. On the other hand, several hybrids were fairly tolerant in the field though the tolerance scores of their parental lines ranged 1 to 5 points. There was no relationship between the ‘emergence – anthesis’ period and cold tolerance. A great degree of uncertainty is associated with predicting field tolerance of sunflower from its cold tolerance assessed by laboratory test. This laboratory test cannot be used to predict field tolerance of either lines or hybrids. There was a strong positive correlation between the field tolerance and seed yield in the lines, but the correlation coefficient for the hybrids indicated no significant correlation between these parameters.
 Conclusions. At non-freezing low temperatures, the yield of the inbred sunflower lines was positively correlated with the field tolerance score at the early stages of plant growth and development. There was no significant difference in responses of early- and medium-ripening sunflower genotypes to cold exposure. Lakhanov’s cold germination test is not appropriate for evaluation of field tolerance in sunflower lines and hybrids.

The ideal harvest time for seed production in maize (Zea mays L.) varieties of different maturity groups.

The correct time for harvesting is a key factor contributing to the production of high-quality maize seeds. We conducted field experiments to harvest seeds at 11 developmental stages for 3 years, to investigate seed vigor traits in three early maturity maize varieties and two late maturity varieties in one location. Significant correlations (r=0.72 ~ 0.89) were found among six seed-related traits: standard germination (SG), accelerated aging germination (AAG), cold test germination (CTG), hundred-seed weight (HSW), seed moisture content (SMC), and ≥ 10°C accumulated temperature from pollination to harvest (AT10). Analysis of variance showed that harvest stage, year, and variety had significant effects on all traits, and harvest stage displayed the greatest effect. The responses of SG, AAG, CTG, HSW and SMC to harvest stage fitted quadratic models, and AT10 fitted a linear model. From the quadratic models, an ideal harvest time (IHT, the final date to reach maximum SG, AAG, and CTG) could be calculated for each variety. The three early maturity varieties reached their IHT at 54.94-58.44 days after pollination (DAP); the two later maturity varieties reached IHT several days later (at 59.87-59.90 DAP). The early maturity varieties consistently required less AT10 to reach the IHT than the later maturity varieties. However, all of the varieties reached the IHT at similar SMC levels of about 35%. The later maturity varieties reached the IHT at later DAPs when they acquired more AT10 than the early maturity varieties but both reached it at similar SMC levels. © 2022 Society of Chemical Industry.

A Comparative Analysis of the Hybrid Maize (Zea mays L.) Seed Quality in China from 2013 to 2018

In this study, a comparative analysis of seed quality indicators of 1196 hybrid maize seed samples from the main maize-producing areas in China from 2013 to 2018 was carried out. The results showed that the maize seed quality in China had changed obviously in the past six years, and was mainly as follows: The percentage of samples with coated seed in 2015–2018 was higher than 62.8% in 2013 and all exceeded 97%; the sample rate of packaging according to seed number was from 24.5% in 2013 to 58.6% in 2018, and the percentage of samples which met the prescribed quality standards was from 89.2% in 2013 to 98.4% in 2018. Principal component analysis indicated that standard germination energy (SGE), standard germination percentage (SGP), cold test germination percentage (CTGP), accelerated aging test germination percentage (AATGP), and mean field seedling emergence (FSE) were the primary predictors of seed germination and seedling emergence. Meanwhile, combining other statistical methods, regression models of SGE, SGP, CTGP, and AATGP were established to predict the field seedling emergence. Furthermore, seed bulk density and total starch content were correlated with seed vigor, which needs to be further studied. This study offered a theoretical basis and data support to better understand the changes of maize quality in China over the past six years, and provided an important reference to further improve the maize seed quality in the future.

Effect of mechanical threshing on damage and vigor of maize seed threshed at different moisture contents

Mechanical threshing used when preparing maize seeds for planting subjects seed to damage and reduces seed quality. The purpose of this study was to assess the effect of mechanical threshing on the quality of maize seed threshed at different moisture contents (MCs). Seeds of dent maize JK968 and flint maize DD2 were threshed at 12, 15, 18, 21, and 24% MC. The damage degree was determined by iodine staining, and seed vigor was assessed by standard germination (SG), cold test germination (CTG), accelerated aging germination (AAG), seedling emergence rate, and seedling root and shoot length. The results showed that the damage percentage increased, and the seed vigor parameters decreased with increasing seed MC during threshing in both cultivars. For obtaining high seed quality, indicated by at least 90, 85, and 80% of SG, AAG, and CTG, respectively, JK 968 and DD2 should be threshed at MC lower than 15 and 18%, respectively. Furthermore, the damage mainly occurred in the apical part of seeds, irrespective of the threshing MC in both cultivars. When the embryo was damaged, seedling emergence rates were significantly reduced with great influence on shoot length. Damage to the endosperm resulted in little effect on seedling performance. Flint maize DD2 was more tolerant to mechanical threshing than dent maize JK968. These results provided technical reference for the production and processing of high vigor maize seeds.

Seed mineral reserves and vigour of Bambara groundnut (Vigna subterranea L.) landraces differing in seed coat colour

A newly emerged seedling, given light and water, but no external source of minerals, uses its internal mineral nutrient reserves effectively for an early establishment. This research sought to investigate the influence of seed coat colour on the abundance of mineral elements in Bambara groundnut. Four landraces (G340A, Kazai, Kazuma, and Mana) varying in seed coat colour were analysed for differences in seed mineral composition using energy dispersive x-ray (EDX) analysis and atomic absorption spectrometry (AAS). Seeds were germinated at 10 °C and 25 °C, and various indices including, (1) mean emergence time, (2) mean germination rate, (3) coefficient of velocity of germination, and (4) final germination percentage (FGP) were calculated. The importance of seed mineral elements in the establishment of Bambara groundnut was examined by measuring root length (RL), shoot length (SL), shoot dry mass (SDM), and root dry mass (RDM). Plant tissue elemental analysis was done using flame atomic emission spectrometry (FAES) for K and flame atomic absorption spectrometry (FAAS) for Mg, Cu, Mn, and Zn. There were significant differences (P < 0.001) in mineral element content of dry seeds. G340A and Kazai had the highest and the lowest K, P, Mg, Mn, and Zn (11.65 gkg-1, 7.2 gkg-1, 2.33 gkg-1, 59.56 mgkg-1, and 44.42 mgkg-1), and (8.82 gkg-1, 4.75 gkg-1, 1.38 gkg-1, 48.9 mgkg-1, and 42.6 mgkg-1), respectively. Cold test germination indices were significantly different, the highest FGP was 73.3% in G340A and the lowest was 57.8% in Kazai. There were strong positive correlations between seed mineral concentration and plant growth parameters (p < 0.001). We concluded that (1) seed mineral concentration has a significant impact on the early establishment of Bambara groundnut and (2) the dark-coloured landraces (hue 8º) used in this study have the highest concentration of macro and micro elements compared to light coloured seeds (hue 38º).

Evaluation of Seed Vigor Tests for Predicting Seedling Establishment at Low Temperature in Rice (Oryza sativa L.)

This study was carried out to develop an evaluation method to predict rice seedling establishment (SE) under low-temperature conditions. Two Korean-bred japonica cultivars, Shindongjin and Hopum were used in the experiment. Fresh seeds were treated with an accelerated aging (AA) at 40°C and 100% RH for 1-15 days. The SEs of the fresh and AA seeds were evaluated in nursery beds at 17°C, and their correlation coefficients with seed vigor values measured by 9 test methods including standard germination test (SGT), cool germination test (CLT), cold germination test (CDT), seedling growth rate test (SGRT), ascorbate peroxidase (APX), peroxidase (POX), superoxide dismutase (SOD), catalase (CAT), and α ‐amylase (AMY) activities. The percentage of SE decreased slowly from 75 to 0% with an increasing of AA period from 0 to 15 days. The result of nine vigor tests showed different correlations with the SE. SGT, CLT, SGRT, and POX were significantly correlated with the SE. In the correlation analysis with only short-term aging seeds (1-7 days), the SE was very highly correlated with SGT, CLT, CDT, SGRT, POX, and CAT. These results suggest that seed vigor values measured by several methods including SGT and POX could be used as a reference value to secure SE at low temperatures in nursery bed rice seedling culture.

The ideal harvest time for seeds of hybrid maize (Zea mays L.) XY335 and ZD958 produced in multiple environments

To identify the ideal harvest time (IHT) for the seed production of XY335 and ZD958, six seed-related traits were evaluated in seeds harvested at 11 harvest stages in 8 environments. Standard germination (SG), accelerated aging germination (AAG) and cold test germination (CTG) were vigor traits; hundred-seed weight (HSW) and seed moisture content (SMC) were physiological traits; and ≥10 °C accumulated temperature from pollination to harvest (AT10ph) was an ecological trait. All the traits were significantly affected by harvest stage. The responses of SG, AAG, CTG and HSW to postponing harvest stage fit quadratic models, while SMC and AT10ph fit linear models. The IHT (indicated by the last date to reach maximum SG, AAG and CTG) were 57.97 DAP and 56.80 DAP for XY335 and ZD958, respectively. SMC and AT10ph at IHT were 33.15% and 1234 °C for XY335, and 34.98% and 1226 °C for ZD958, respectively. The period to reach the maximum HSW was 5 days later than the IHT. Compared to HSW and SMC, AT10ph had a closer relationship to the seed vigor traits. Together with the fact that AT10ph was less affected by environment, these results suggested that AT10ph may be a novel indicator for determining the IHT.

Evaluation of sweet sorghum accessions for seedling cold tolerance using both lab and field cold germination test

Objective: Seedling cold tolerance is one of the important traits for sweet sorghum production. This study is to evaluate the method for identification of sweet sorghum accessions with seedling cold tolerance using both lab cold germination and field early-spring cold planting. Methodology: Sorghum seeds were germinated in growth chamber (under lab cold condition) at a constant 12°C for five weeks. After two weeks, germinated seeds and germination rates were counted and calculated at weekly intervals for four times. The same seed lots for lab cold test were also planted 45 days earlier than the normal planting time in the field (early-spring cold planting). In addition to seedling dry weight, germinated seeds and seed germination rates were also counted and calculated at weekly intervals for three times. Results: In this study, a high correlation coefficient between lab germination rate and field germination rate (R2=0.503, p<0.0001) was observed. In general, lab germination rate can predict the field germination performance; but some discrepancies between field and lab tests were also observed for some accessions. Among 212 sweet sorghum accessions tested, several sweet sorghum accessions with seedling cold tolerance were identified from both lab and field tests. These accessions will be useful materials for development of sweet sorghum cultivars with early spring cold tolerance. Conclusion: Compared with the field test, the lab test is less labor intensive. For a large-scale screening of seedling cold tolerance, the lab test may be conducted initially followed by selection of superior accessions from the lab test for further evaluation under field conditions.

수수의 종자형태 및 발아세 평가

본 연구는 수요와 재배면적이 점차 확대되고 있는 수수의 안정적인 생산을 확립하기 위한 기초자료로 활용하고자 주요 4품종(남풍찰, 동안메, 황금찰, 흰찰)을 이용하여 종자의 형태적 특성과 다양한 종자세 검사 등 종자의 기본적인 특성을 알아보았다. 1. 수수의 형태적 특성에서는 폭을 제외한 장과 두께는 차이가 나타나지 않았으며, 종실형태는 흰찰은 원형, 나머지 품종은 난형의 형상으로 보였다. 종피색에서는 흰찰과 나머지 품종간의 뚜렷한 차이를 보이며, 남풍찰과 황금찰은 무광택 종자이었다. 2. 표준발아검사 및 저온검사는 황금찰>남풍찰>동안메>흰찰 순으로 나타났고, 노화촉진검사에서는 표준발아 검사와 비교시 동안메에서만 15% 이상의 감소를 보였으며, 전기전도율 검사는 표준발아검사, 저온검사 및 노화촉진검사의 발아율과 부의 상관관계를 나타났다. 3. 출현율 평가에서는 황금찰이 가장 높은 85.7%로, 가장 낮은 출현율을 보인 흰찰보다 40% 이상의 차이가 나타났고, 평균 출현율일수에서는 흰찰이 가장 느린 6.0일로 보이며 품종별 뚜렷한 차이가 나타났다. This study was conducted to evaluate basic seed characteristics such as morphological characteristics and various seed vigor using 4 sorghum varieties, Nampungchal, Donganme, Hwanggeumchal and Whinchal. No difference was shown in morphological characteristics of the varieties except that the width. Whinchal has bulb-shaped seed, while the other varieties have oval-shaped seeds. The seed coat color of Whinchal is obviously different from those of the other varieties; especially, Nampungchal and Hwanggeumchal are not glossy. Germination rate were Hwanggeumchal > Nampungchal > Donganme > Whinchal in the order of higher rate in standard germination tests and cold germination test. In the ageing test, Donganme showed the lowest 15% decrease in comparison with the standard cultivar. Electric conductivity (EC) has negative correlation with standard germination tests, cold germination test and accelerated ageing test. In the percentage of emergence (PE), Hwanggeumchal was the highest 85.7% which was more than 40% to the lowest Whinchal. Mean emergence time (MET) showed significant difference between the varieties; Whinchal showed the slowest 6.0 days.

팥 포장출현력 예측을 위한 종자세 검사

경실로 인해 다른 두과작물에 비해 포장 입묘가 불량한 팥의 포장출현율의 효과적인 예측 방법을 개발하기 위해 인위로 노화 정도를 조절한 종자에 대해 실험실에서 몇 가지 종자세 검사를 실시하여 포장출현력과 비교하였다. 얻어진 종자세 지표들에 대해 포장출현력과의 상관분석을 통해 예측을 위한 효율적인 지표들을 도출하였다. 팥에서 종자세가 높을 경우에는 표준발아검사에서의 종자활력률이 포장출현력 예측에 효과적이며, 약간 노화된 종자의 경우에는 저온발아검사(CGT)에서의 비정상묘율과 배축의 길이는 포장출현력과 높은 상관관계를 보였으며, 전기전도도와 CSVT에서의 활력률과 테트라졸리움 검사에서 종자세와 예측발아율은 포장출현력과 5% 수준에서 상관관계가 인정되었다. 종자세가 낮은 종자에서는 CSVT에서 불발아종자율이 포장출현력과 5% 수준에서 상관을 보였다. 포장출현력 예측에 효과적인 몇 가지 종자세지수를 이용하여 stepwise multiple regression 분석을 실시한 결과 테트라졸리움(TZ) 검사에서의 예측발아율은 결정계수(<TEX>$R^2$</TEX>)가 0.820으로 포장출현력 예측에 가장 효과적인 검사방법임을 알 수 있었다. 표준발아검사(SGT)에서의 종자활력률, 저온발아검사(CGT)에서의 정상묘율과 건물중을 회귀방정식에 추가함에 따라 86.9% 까지 포장출현력 예측효율을 증가시킬 수 있었다. Field emergence of Azuki bean is poor due to hard seed coat as compared to other legumes. In this study, an attempt was made to develop prediction method with regression analysis based on various seed vigor tests in laboratory for field emergence of azuki bean. Azuki bean seeds artificially aged to provide various levels of seed quality were evaluated by the standard germination test (SGT), cold germination test (CT), cool germination test (CGT), complex stressing vigor test (CSVT), tetrazolium(TZ) vigor test and electroconductivity test. The SGT was suitable for predicting the field emergence in the unaged high vigor seeds. The abnormal seedling percentage and shoot length in the CGT were highly correlated with field emergence of moderate vigor seeds artificially aged for 2 days. Electroconductivity, seed viability in the CSVT, and vigor and predicted germinability in the tetrazolium vigor test were also useful for predicting field emergence. Percent of ungerminated seed in the CSVT was correlated with field emergence in the low vigor seeds artificially aged for 4 days. In a stepwise multiple regression analysis, seed viability in the SGT, normal seedling percentage and dry matter weight in the CGT accounted for 86.9% of the predicted value of field emergence in azuki bean.

Assessment of Seed Viability and Vigour in Neem (Azadirachta indica A. Juss.)

Rapid loss in viability of neem (Azadirachta indica A. Juss.) seed is a major problem. Present effort was undertaken for developing a set pattern for assessing of viability and vigour in seed of various mother tree age of neem (Age I-06 years, Age II-15 years, Age III-25 years and Age IV->30 years old). Various viability test viz. triphenyle tetrazolium chloride test, electrical conductivity, excised embryo test, and germination test have been performed on seeds obtained from mother tree age classes. Inconsistency was observed with the TTC and EC test in germination of seed in laboratory as well as nursery. While various vigour tests viz. cold test, chemical stress test (methanol stress test), and accelerated ageing test alongwith ageing index, germination test (G%, MGT and GV) and various seedling growth parameters like seedling length (cm), number of leaves, collar diameter (cm), total biomass (g) alongwith mathematical indices i.e. vigour index, sturdiness quotient, volume index, quality index, root shoot ratio in nursery as well have been taken for study and showed better consistency. On the basis present study results of various viability and vigour test indicated that mother tree age class II performed better in comparison to others and it can be recommended for seed collection. Further it is also recommended that viability of neem seed may be assessed using various laboratory tests like excise embryo test and germination test (G%, MGT and GV) and vigour test may be taken preferably by cold germination test, chemical (methanol) stress test, accelerated ageing test in laboratory and germination alongwith various seedling growth parameters seedling length (cm), number of leaves, collar diameter (cm), total biomass (g) alongwith mathematical indices like Vigour Index, Sturdiness quotient, Volume Index, Quality index, root shoot ratio in nursery as discussed in this study.

ASSOCIAÇÃO DE AGROTÓXICOS AOS TEORES FOLIARES DE MICRONUTRIENTES E À PRODUTIVIDADE E QUALIDADE FISIOLÓGICA DE SEMENTES DE SOJA

Glyphosate effects on leaf micronutrients contents of transgenic soybean have been widely reported, however, little is known about these effects associated with other pesticides. The objective of this study was to evaluate the physiologic quality and yield of soybean seeds, as well as leaf micronutrients contents, according to weed control methods. Ten RBD treatments were arranged in a split-plot scheme with four replications. The application or non-application of endosulphan + tebuconazole was evaluated in the plots, while the weeds control methods were assessed in the subplots (weeded control; non-weeded control; single application of glyphosate (1,080 g ha -1 ) and fomesafen + fluazifop-?-butil (180 + 225 g ha -1 ), both at 15 DAE; and sequential application of glyphosate (1,080 g ha -1 ) at 15, 30, and 45 DAE). After harvesting, the soybean seeds were sampled, in order to evaluate their germination, vigor, and yield. Copper and manganese contents were only influenced by the sequential application of glyphosate, associated with endosulphan + tebuconazole. The cold test germination was reduced in seeds of plants treated with fomesafen + fluazifop-p-butil associated with endosulphan + tebuconazole. Among the treatments without endosulphan + tebuconazole, the sequential application of glyphosate promoted the highest 100-seeds weight, as well as, when associated with endosulphan + tebuconazole, reduced the leaf concentrations of Cu and Mn, however, it improved seeds germination and showed no effects on seeds vigor, when compared with the weeded soybean.

Improving Emergence of Modified Phosphorus Composition Soybeans: Genotypes, Germplasm, Environments, and Selection

Commercial production of soybeans [Glycine max (L.) Merr.] with reduced phytate and increased inorganic phosphorus has nutritional benefits but is challenged by poor seedling emergence. An agronomic trial evaluated emergence of advanced lines derived from the CX1834 and V99‐5089 low phytate germplasm at six locations in 2009 and 2010. In 2010, seed produced in 12 environments was evaluated in an extended cold germination test (ECGT) and in a replicated field emergence test in Warsaw, VA. Objectives were to evaluate ECGT as a selection tool for improving germination and emergence of low phytate soybeans and to determine the effect of the seed production environment on emergence in different low phytate soybean germplasm. Genotypic, environmental, and the genotype × environment interaction effects were significant (p &lt; 0.001) for emergence in the agronomic trial, ECGT, and field emergence test. Three lines were not significantly different from the two control cultivars for emergence in 12 environments. Yields of the best emerging lines were not significantly different from the control cultivars. The ECGT and field emergence test were significantly correlated (r = 0.78) but the ECGT severely reduced germination as compared with the field emergence test. Poor germination in the ECGT did not always translate to poor emergence under field conditions, preventing the use of ECGT as a selection tool or in determining seeding rates for the Southeast and Mid‐Atlantic regions.

Pod Yield and Mineral Concentration of Four Peanut Cultivars Following Gypsum Application With Subsurface Drip Irrigation

Abstract A 2-year study (2004 and 2005) was conducted where gypsum was applied to four peanut (Arachis hypogaea L.) cultivars and irrigated with subsurface drip to determine pod yield and mineral concentration of peanut plants and kernels. Gypsum rates were none, 560 and 1120 kg/ha. Peanut cultivars were C99R, Georgia Green (GG), NCV-11 (NCV), and GA-O2C (O2C). Irrigation was applied daily with subsurface drip irrigation except when precipitation exceeded the estimated daily water requirement. Average soil Ca and S concentrations increased as gypsum was applied, 5% and 20%, respectively, compared with the non-treated control. The average soil calcium to potassium (Ca∶K) ratio increased to 9.8∶1 compared with 7.6∶1 prior to applying calcium. When averaged across calcium rates, peanut leaves had 3 and 14 times higher calcium and 1.4 times higher S concentrations compared with pegs and pods, respectively. The cultivars GG and NCV had the same pod yield. Cultivars C99R and O2C had the same yield as NCV but were less than GG. Germination rates were higher when gypsum was added compared to the non-treated control and with cultivars C99R and O2C. There was no difference in vigor by gypsum application rate. Kernel Ca concentration was higher with the addition of gypsum compared to the non-treated control. Cold test germination seed vigor increased with C99R and O2C compared with GG and NCV.

O teste de frio sem solo em sementes de abóbora

Este trabalho teve como objetivo determinar o período de exposição à baixa temperatura no teste de frio sem solo, para avaliação de diferentes potenciais fisiológicos em lotes de sementes de abóbora. Foram avaliados seis lotes de sementes de abóbora cultivar "Menina Brasileira" (Cucurbita moschata Duch.) produzidas na safra 2003/2004. As sementes foram submetidas a diferentes períodos (três, cinco, sete e nove dias) de exposição à baixa temperatura para condução do teste de frio sem solo, a uma temperatura constante de 10°C. Utilizou-se o delineamento inteiramente casualizado, em que os tratamentos constituíram um fatorial 6x4 (seis lotes e quatro períodos de exposição), com quatro repetições de 50 sementes. As médias foram comparadas pelo teste de Tukey em nível de 5% de probabilidade de erro. Realizou-se também o teste de correlação simples de Pearson .Os resultados permitiram concluir que o período de três dias de exposição à baixa temperatura foi o mais indicado para a condução do teste de frio sem solo em sementes de abóbora.

Effect of seed treatment emulsifiers on seed quality and membrane function in maize

Abstract Three commonly used seed treatment emulsifiers, Triton X-100, Proprietary-adjuvant A and Proprietary-adjuvant B, were applied to four seed lots differing in genotype, and seed vigor. Seed quality was measured by cold germination test, leachate conductivity, and sugar leakage. Membrane repair capacity during imbibition, and also membrane lipid composition and thermal properties, were determined. Seed and seedling performance as indicated by germination tests showed no significant difference between control and treated seed in the two high-vigor seed lots. All three emulsifiers, especially at high treatment rates, significantly reduced the performance of the two low-vigor seed lots. Conductivity and cold test germination were not related. However, a high correlation was found between sugar leakage and cold test germination following emulsifier treatment. The occurrence of membrane repair and the associated changes in phospholipid composition and thermal properties in the emulsifier-treated seed indicate a modification of the membrane function due to the emulsifier or adjuvant treatments.

Seed Quality Effect on Corn Performance under Conventional and No-Tillage Systems

In northern regions, no-tillage corn (Zea mays L.) planting often results in reduced and/or delayed seedling emergence and growth. The objective of this research was to evaluate the effects of seed quality on the performance of three commercially available corn hybrids grown with conventional-tillage (CT), no-tillage (NT), and no-tillage with in-row residue removed (NT-R). Field studies were conducted under the three tillage systems with seed lots having high (95–99%), medium (89–98%), and low (84–95%) warm and cold germination test values. Hybrids used were FR20A × FR31, LH74 × LH51, and A632 × LH39. The studies were conducted from 1986 to 1988 on Piano silt loam (fine, mixed, mesic Typic Arguidoll) soils near Arlington and Janesville, WI. There were also early (mid- to late April) and late (mid- to late May) planting dates at Arlington. Increased residue cover with NT and NT-R systems resulted in 2 to 4 °F cooler soil temperatures at planting compared to CT, which reduced average percentage corn emergence by 3%, delayed emergence by 2 to 5 d, reduced vegetative dry weight at 45 d after planting by 30 to 60%, delayed silking 5 to 7 d, and increased harvest grain moisture 1 to 5%. Average grain yields were also reduced by 9% under NT compared to CT. Compared to high quality seed, medium and/or low seed quality caused 4 to 6% lower emergence, delayed emergence less than 1 d, reduced vegetative dry weight by 10 to 15%, extended days to silking by 1 to 2 d, increased grain moisture about 1%, and decreased average grain yield by 4% (despite thinning to constant final stands). Seed quality effects were usually smaller than tillage system effects, and tillage system by seed quality interactions were infrequent. Special concern about seed quality under NT is unwarranted, but to optimize probability for high yields growers should plant high quality seed regardless of the tillage system used.

Effects of Safener CGA-154281 on Metolachlor/Atrazine Injury to Corn (Zea mays)

Three seed lots each of two varieties of field corn were compared in greenhouse and field studies. Cold test germination percentages of the seed lots were as follows: 79, 85, and 93% for ‘DK656’; 77, 84, and 91% for ‘T1100’. Tank mixes of metolachlor or metolachlor with safener CGA-154281 plus atrazine or formulated metolachlor/atrazine with and without the safener were applied preemergence. Crop stand of either variety or among seed lots within a variety was not affected by herbicide treatments. In the greenhouse, fewer corn plants were injured and growth of plants was greater with herbicides with safener than herbicides without safener. Plant heights and weights at harvest from the most vigorous seed lot of DK656 were higher than those of the other two seed lots. Herbicide treatments with the safener did not cause significant injury to corn in the field. Yields of both varieties increased with herbicide treatments in one conventional planting. No significant differences in injury or yields occurred among seed lots within varieties.

Rapid Isolation and Measurement of Adenosine Triphosphate Levels in Corn Embryos Germinated at Suboptimal Temperatures

The trend towards earlier planting dates and conservation tillage systems in corn (Zea mays L.) production has prompted interest in accurate methods for predicting cold tolerance in germinating seedlings. Measurement of nucleotide phosphate levels in germinating seed has been proposed as one such method, but has proven to be a tedious procedure to apply to plant materials. A nucleotide extraction technique was combined with high performance liquid chromatography (HPLC) and applied to the measurement of adenosine triphosphate (ATP) in germinating corn embryos. Embryo ATP concentrations were determined for seed lots of two corn hybrids imbibed over a 96‐h period at two temperatures, 10 and 20 °C. The lower temperature reduced ATP levels and accumulation rates for both cultivars. Differences in the embryo ATP concentrations of the respective hybrids were apparent after 32 h of imbibition at 10 °C. Differences in the ATP accumulation rate of those embryos were detectable 4 to 16 h into the germination process. Significantly lower quantities of ATP in one hybrid (Dekalb‐Pfizer XL 72B) germinated at 10 °C for 64 h were associated with a corresponding reduction in cold‐test germination percentage of that seed. Measurement of embryo ATP levels for six additional hybrid seed lots after 64 h of germination at 10 °C revealed significant variations in ATP concentration. Correlation of embryo ATP levels and cold‐test germination percentages with the field performance of these hybrids indicated that embryo ATP levels were a more reliable predictor of cold tolerance than the cold germination test.

Planting Seed Density in Relation to Cotton Emergence and Yield

AbstractCotton (Gossypium hirsutum L.) planting seed density has been related to seedling emergence and vigor, although its effects on yield are not clearly understood. Seed lots of the cultivar ‘DP90’ were separated into four density classes using a gravity separation table. These seed classes were evaluated along with an undivided seed sample and a sample from processed seed selected for commercial use. The seed classes were planted at three planting rates in seven tests conducted from 1983 to 1985 at Maricopa, Marana, and Safford, AZ. The soils at these locations are Typic Camborthids, Thermic Torrifluvents, and Typic Torrifluvents, respectively. The lowest density seed had significantly lower standard and cold germination test results; however, there were no differences among the other five seed classes in 2 of the 3 yr. Field emergence of the highest density seed was significantly greater than that of the other density classes for the seven tests combined, and was significantly lower for the lowest density seed. Lint yields produced by plants from the highest density seed were significantly greater than those of the four other seed classes, and the lowest density seed produced significantly lower yields. There were no significant interactions between planting seed density and planting rate for yield. The results indicate that cotton planting seed quality could be improved slightly by selecting higher density seed