Seed Vigor Measurements for Predicting Field Establishment of Pearl Millet

Abstract

Seed vigor is one of the many problems that limit grain millet production because it affects field establishment and, thus, yields. The purpose of this study was to measure vigor in grain millet seeds and select from common vigor tests, the one most appropriate for pearl millet. We used 20 varieties in 1977 and 30 in 1978 to investigate the ability of standard germination, electrical conductivity of soaked seeds, NH4Cl and NaOH stress tests, artificial aging, and soil cold testing to predict field establishment. Field establishment counts were made on three planting dates in 1977 and four in 1978 at Manhattan and two planting dates at St. John in 1978. Germination percentages from the stress tests were lower because stress killed seeds of low vigor while vigorous seeds remained relatively unaffected. Criteria used to evaluate laboratory vigor tests included correlation with field establishment and ability to rank millet varieties according to field performance. NaOH, NH4C1, accelerated aging, and standard germination treatments were significantly (0.01 level) similar in ranking seed lots according to vigor. Standard germination results are commonly used to predict field establishment, but standard germination often overestimates field establishment (Vanderlip et al., 1973). Barnes (1960) and Vanderlip et al. (1973) concluded that field establishment of a seed lot should be predicted from germination percentages from a stress test because weaker or nonvigorous seeds would be killed and, as in the field, only vigorous seeds would survive. Seed and seedling vigor particularly affect field establishment of proper plant populations. Algarswamy et al. (1977) indicated that genetic differences Contribution 79-241-J, Agron. Dep., Kansas Agric. Exp. Stn., Manhattan, KS 66506. Part of a thesis submitted by the senior author in partial fulfillment of requirements of the M.S. degree. Supported by funds from the Ford Foundation and USAID, Washington, D.C. Contracts No. AID/ta-c-1458 and AID/DSAN-G-0149, Title XII, INTSORMIL. 2 Present address: Kilombero Sugar Co., Ltd., Kidatu, Tanzania. This content downloaded from 157.55.39.162 on Thu, 11 Aug 2016 06:23:13 UTC All use subject to http://about.jstor.org/terms 58 TRANSACTIONS OF THE KANSAS ACADEMY OF SCIENCE Table 1. Average germination percentages from indicated laboratory vigor tests. Laboratory test 1977 1978 Standard germination 79.3 85.8 NH4Cl treatment 71.9 81.2 NaOH treatment 51.9 58.7 Accelerated aging 30.8 65.5 Cold test 17.1 Vigor analyzer 30 min soaking 63.8* Overnight soaking 85.4* * Percentage identified as vigorous by the analyzer, not percentage germinated. in seedling vigor among pearl millet [Pennisetum americanum (L.) K. Schum] genotypes could be distinguished by visually scoring the plants under field conditions. Mahadevappa (1968), who found no differences among pearl millet parents and hybrids in germination, reported significant differences in rates of respiration, seedling height, fresh weight, root-to-shoot ratio, total root length, and leaf area. Our research measured vigor in grain pearl millet varieties and evaluated these varieties with vigor tests used on other crops. MATERIALS AND METHODS Laboratory tests Laboratory tests in 1977 were: standard germination (Anonymous, 1954), soaking seeds in 2% ammonium chloride solution for 2 hours (Helmer et al., 1962), artificially aging seeds at 400C and 84% relative humidity for 10 days (Abdullahi and Vanderlip, 1972), soaking seeds in 5% sodium hydroxide solution for 2 minutes (Barnes, 1960), and cold testing (Abdullahi, 1968). Seeds were rinsed in water after NH4C1 and NaOH treatments before germination. Twenty varieties with 50 seeds per seed lot replicated 4 times were used in both field and laboratory tests. In 1978 a different set of 30 seed lots was used and seed number per treatment was increased to 100. The same tests and procedures were used except electrical conductivity (Vigor Analyzer)3 of seeds soaked either for 30 minutes or overnight replaced the cold test. Field experiments At Manhattan in 1977, a split plot design was used with 3 planting dates 3 Equipment provided by AgroSciences, Inc., Ann Arbor, Mich. Use of product names does not imply endorsement over similar products not named. This content downloaded from 157.55.39.162 on Thu, 11 Aug 2016 06:23:13 UTC All use subject to http://about.jstor.org/terms VOLUME 89, NUMBERS 1-2 59 Table 2. Simple correlations between pearl millet field establishment and laboratory vigor tests. Laboratory vigor tests Location, year, and date