Anther‐Derived Dihaploids for Lodging Improvement in Tobacco

Abstract

Lodging due to severe weather conditions is observed in crops each year. A 2‐yr study was conducted to determine the effectiveness of anther‐derived dihaploids for improving lodging resistance, and to examine certain morphological traits which may contribute to lodging in Maryland tobacco (Nicotiana tabacum L.). Forty‐five and 35 dihaploid lines were derived from F1 plants of ‘MD 201’ ✕ ‘Catterton’ (Population 1) and MD 201 ✕ ‘NC 13’ (Population 2) crosses, respectively, using standard anther and midvein culture techniques. Mature plants were subjected to artificially produced wind, and evaluated by a severity rating based on the degree of lean from the vertical position. Significant variation amongth e dihaploid lines was observed for severity rating over the 2 yr. Heritability values for Populations 1 and 2 were 0.61 and 0.64, respectively. Based on severity ratings from the first year field study, five good and five poor dihaploid lines in Population 2 were evaluated in a 2‐yr greenhouse study for top and root fresh weights and top/root ratio (TRR). Significant variation was observed among the 10 dihaploid lines for TRR only; however, the five lines selected for good lodging performance had larger root weights and smaller TRR than the five lines selected for poor lodging performance. Results obtained from these field and greenhouse studies suggest that the development of dihaploid lines with low severity ratings, larger roots, and smaller TRRis possible, and should provide superior genetic material with a good level of lodging resistance.

Genetic analysis of root traits in maize

“…Five [19], using PLABQTL computer package [28]. A These results seem to contradict previous studies [11,14,15,20] internode after the previous one is completed [22], high associations of the potential of root emergence on the last two internodes could be expected, as the expression of the growth potential permitted by environmental factors.…”

“…This damage is important in northern temperate regions as well as in the Tropics [24]. The most commonly used criterion for comparing maize [27,31], its weight after pulling out [17,27], the volume of roots [31], the number of roots on the upper internodes [7,15], the angle of root growth from the stem [5, 11, 15, 26], the diameter of the roots [15,25], the number of internodes with emerged roots [21], the stalk diameter [20], the length of the base internodes of the plant [15]. It has been observed that the total number of roots is not strongly correlated with the lodging resistance [16].…”

Selection of soybean elite cultivars based on phenotypic and genomic characters related to lodging tolerance

“…Lodging is a complex trait involving multiple genes and their interactions with the environment (Lee, Bailey, Mian, Carter, et al., ; Lee, Bailey, Mian, Shipe, et al., ; Liu et al., ; Orf et al., ; Panthee, Pantalone, Saxton, West, & Sams, ). Its severity has been closely related to population density, as plants tend to be prostrate as population density increases (Cooper, ), and it is correlated with both aboveground (e.g., plant height and stem strength) and underground (e.g., root weight and root length) traits (Inoue, Gao, & Cai, ; Keller et al., ; Menchey & Aycock, ; Tar'an et al., ). Although the low efficiency of phenotypic selection for complex traits is a major limitation for plant breeding, biotechnological advances have allowed identifying genetic variations associated with lodging tolerance and enhancing the efficiency of lodging selection in soybean breeding using marker‐assisted selection (MAS).…”

Effectiveness of combining resistance to Thielaviopsis basicola and Tomato spotted wilt virus in haploid tobacco genotypes

“…The method resulted in the development of doubled haploid lines which combined satisfactory agronomic performance with resistances to Tobacco mosaic virus , Phytophthora parasitica and Pseudomonas syringe ( Walker and Aycock 1994 ), PVY ( Hamada et al . 2001 ) or with resistance to lodging ( Menchey and Aycock 1998 ). Combining resistance to Tobacco mosaic virus , Pseudomonas syringae pv.…”