such as rate of crop maturity, bulb size and color, clove size and number, leaf number and color, and bolting habit. Variation observed in genetic diversity studies using molecular markers is as wide as that observed for phenotypic variation among the
Meryem Ipek, Ahmet Ipek, Douglas Senalik and Philipp W. Simon
Jessica Chitwood, Ainong Shi, Beiquan Mou, Michael Evans, John Clark, Dennis Motes, Pengyin Chen and David Hensley
. ) ( Nemli et al., 2014 ), and heat tolerance in cowpea ( Lucas et al., 2013 ). Some of the major agronomic traits of interest in spinach are bolting, plant height, and leaf erectness. Bolting is an important trait to consider in relation to developing
Sylvie Jenni, Isabelle Gamache, John Christopher Côté and Katrine A. Stewart
Growers of early stalk celery (Apium graveolens var. dulce) often experience financial losses due to bolting (the premature and rapid elongation of the main celery stem) in temperate regions. A method was developed to provide early warning of bolting in field-grown celery, on the basis of two criteria, one visual and one microscopic, for inflorescence development. Bolting could be detected 40 days after transplanting using the visual criterion, and as early as 30 days after transplanting using the microscopic criterion. Early detection of bolting using the visual and microscopic criteria provided celery growers with periods of, respectively, 25 days and up to 35 days to consider harvesting earlier, before the length of the celery stems exceeded commercial standards. This method could be effective in minimizing financial losses due to bolting when coupled with agro-economic studies.
Ren-Huang Wang, Yu-Mei Hsu, Duane P. Bartholomew, Subbiyan Maruthasalam and Chin-Ho Lin
regarding the number of treatments and frequency of AVG application are given in Table 1 . Plants treated with 5 ml of an aqueous solution containing 0.02% Break-Thru alone were kept as a control. Inflorescences emerged in the leaf whorl, defined as bolting
Lynn Brandenberger, Todd Cavins, Mark Payton, Lynda Wells and Tina Johnson
bolting resistance. Yield has been included in a majority of studies and is considered to be a key component of cultivar selection ( Dainello et al., 1987 ; Djurovka et al., 1988 ). The presence of dark green color in spinach is an important aspect of
Smiljana Goreta and Daniel I. Leskovar
Areas with mild climate conditions are suitable for growing winter spinach (Spinacia oleracea L.). Successful production depends on choosing slow-bolting cultivars resistant to major diseases in each area. Field experiments with a total of 18 cultivars were conducted during 8 years in the Winter Garden region of Texas, an area known for its high white rust (Albugo occidentalis G.W. Wils) inoculum. Spinach cultivars differed widely in their resistance to both white rust and bolting, and the incidence of both traits was more severe as the season progressed. White rust infection increased linearly with average monthly minimal air temperature. Cultivars Fidalgo, Springfield, and Springer were slow bolting and are suitable for areas with no white rust incidence, while cvs. ASR-318, DMC 66-09, Fall Green, Samish, and San Juan were more white rust resistant.
Douglas C. Sanders and Jennifer D. Cure
The efficacy of undercutting as a technique to control bolting of two short-day onion cultivars was studied in controlled-environment chambers. `Buffalo' and `Granex 33' onions were grown to the third, fifth, and seventh visible leaf stages in a 10-hour photoperiod at 22/18 °C (day/night) and then exposed to 30, 40, 50, 60, or 70 days of vernalizing temperatures (10/10 °C). Half of the plants were undercut at the initiation of the vernalizing treatment. After vernalizing treatments, plants were returned to 14-hour photoperiods at 22/18 °C. `Buffalo', which is resistant to bolting, did not flower significantly under any of these conditions. The flowering response of `Granex 33' increased with leaf number at vernalization and as the duration of vernalization increased. Undercutting `Granex 33' increased the days of vernalization required for flowering and reduced the proportion of flowering relative to controls. Overall dry-matter accumulation was unaffected by leaf number at vernalization or the duration of vernalization but was reduced ≈30% by undercutting. In both cultivars, fresh mass per bulb decreased with increasing leaf stage of vernalization and number of vernalizing days. Undercutting also decreased fresh mass per bulb, but through its effect on bolting, undercutting increased marketable yield for plants vernalized and undercut at the fifth and seventh leaf stages.
Jongtae Lee, Byeonggyu Min, Heedae Kim, Juyeon Kim, Young-Seok Kwon and George E. Boyhan
of stand reduction because of winter frost injury. High temperatures during root establishment could cause doubling or bolting, whereas low temperatures could result in poor root establishment, growth retardation, or frost injury. Heavy or frequent
Ryan J. Hayes, Bo Ming Wu, Barry M. Pryor, Periasamy Chitrampalam and Krishna V. Subbarao
other types of cultivated lettuce are known and encompass extensive variation for leaf color, texture, shape, growth habit, and the time to initiation of bolting ( Ryder, 1999 ). These types include red and green leaf, butterhead, and the lesser known
Timothy Coolong and Mark A. Williams
Georgia, which typically experiences mild winter temperatures ( Boyhan and Kelley, 2007 ). Table 1. Survival and flowering (bolting) percentage for seven onion cultivars grown overwinter in 2007–08 and 2008–09 with rowcovers [R (AG 50 ® ; Agribon