GENOTYPIC AND PHENOTYPIC CORRELATION AND PATH ANALYSIS FOR LODGING RESISTANCE TRAITS IN BREAD WHEAT (Triticum aestivum L.)

Abstract

Relationships between the traits associated with lodging resistance in wheat were studied within the period of 1999-2002 at Wheat Research Center, Dinajpur in both F 1 and F 2 generations of a 9 × 9 diallel cross without reciprocal. The genotypic and phenotypic correlation coefficients studied in F 1 and F 2 generations were similar with some exceptions. In both F 1 and F 2 generation, the second internode breaking strength was positively correlated with diameter, wall thickness and unit-stem weight of second internode, and main shoot weight but negatively with plant height and second internode length at both genotypic and phenotypic levels. It was observed from path coefficient analysis in both F 1 and F 2 generations that the second internode unit-stem weight had high positive direct effect on it's breaking strength. Main shoot weight, second internode diameter and wall thickness positively influenced breaking strength through its unit-stem weight. Simultaneous selection for the traits contributing to lodging resistant in semi-dwarf wheat might be effective in the improvement of lodging resistance in bread wheat. Key words: Wheat (T. aestivum L), lodging resistance, genotypic, phenotypic, correlation, path analysis, INTRODUCTIONLodging is a complex event, which is influenced by many morphological and anatomical plant traits such as culm length, basal internode length, culm diameter, wall thickness as well as breaking strength or elasticity of culm tissue, culm density, culm anatomy and chemical compositions of stem and root characters, head density and size etc. with some environmental factors. Lodging may occur in the lower two-three internodes of the plant. Pinthus (1973) observed that the lowest three or four internodal lengths have a greater effect on lodging. Stem lodging of wheat is greatly depends upon straw strength. Study of relationships between some important traits associated with lodging is very much important in choosing a suitable selection criterion for lodging resistance. The ideas about the association of lodging with some plant characters could be better explained through correlation coefficient study. Correlations among morpho-physiological characters are helpful in determining the components of complex traits like biomass, yield, lodging etc., but they did not provide an exact picture of the relative importance of direct and indirect influences of each of the component characters. The breeding strategies differ with the nature of association of these characters. Therefore, the relationships have been further analyzed by phenotypic and genotypic correlation coefficients. Then performed path coefficient analysis to disclose the cause and effects of chain relationships of different contributing characters with the most important character related to lodging resistance in bread wheat. The present investigation was undertaken to study the genotypic and phenotypic correlation and then path analysis for the traits associated with lodging resistance in bread wheat.

Improving Lodging Resistance: Using Wheat and Rice as Classical Examples

“…The short length of primary internodes can support to construct an ideal culm structure for resistance to lodging whereas the reduction in the length of the upper internode could have an adverse impact on panicle exertion [42,43,44]. A negative relationship of the basal internode length with lodging score has been observed, which suggests that the longer internodes at base could result in a higher lodging score in wheat [45] and rice [46].…”

A mechanistic view on lodging resistance in rye and wheat: a multiscale comparative study

“…Plant height is usually negatively correlated with basal internode breaking strength, suggesting that short varieties are more resistant to lodging (Börner and Korzun, 1998 ; Crook and Ennos, 1994 ; Miedaner et al ., 2012 ; Sarker et al ., 2007 ). Consequently, the Rht dwarfing alleles have been successfully used for breeding lodging‐resistant wheat.…”