Development of new canola (Brassica napus L.) cultivars requires efficient tools to monitor trait association in a breeding program. The efficiency of a breeding program depends mainly on the direction of the correlation between yield and its components and the relative importance of each component involved in contributing to seed yield. This research uses sequential path analysis to determine the interrelationships among seed yield and 20 related traits. Forty nine canola genotypes were grown in two environments (non-stressed and water-stressed conditions) to determine the important components of seed yield. Observations were recorded on 20 other canola traits. Correlation coefficient analysis revealed seed yield was positively correlated with all the traits except stem diameter and days to flowering in the non-stressed environment. Seed yield was significantly positively correlated with all measured traits except first pod height, first lateral branch height, number of lateral branches pod -1 , number of pods plant -1 and stem diameter in the water-stressed environment. Sequential path analysis identified the 1,000-seed weight (TSW) and main stem length as important first order traits that influenced seed yield in the non-stressed environment. Plant height and the TSW were important first order traits that influenced seed yield in the water-stressed environment. All direct effects were significant, as indicated by bootstrap analysis. The results suggest that TSW could be used as a selection criterion in selecting for increased seed yield in canola in both non-stressed and water-stressed conditions. Additional key words: bootstrap analysis, conventional path analysis, drought tolerance. Resumen Interrelación entre el rendimiento de las semillas y veinte caracteres asociados de 49 cultivares de colza (Brassica napus L.) en entornos sin estrés y con estrés hídricoEn los programas de mejora, el desarrollo de nuevos cultivares de colza (Brassica napus L.) requiere herramientas eficaces para analizar la correlación entre el rendimiento de las semillas y sus componentes genéticos. La presente investigación utiliza un análisis secuencial para determinar las interrelaciones entre el rendimiento de las semillas y 20 caracteres relacionados. Se cultivaron 49 genotipos de colza en dos ambientes (sin estrés y con estrés hídrico) para determinar los componentes más importantes del rendimiento de las semillas y se realizaron observaciones sobre otros 20 caracteres. El análisis del coeficiente de correlación reveló que el rendimiento de las semillas está positivamente correlacionado con todos estos caracteres, excepto con el diámetro del tallo y días hasta la floración en condiciones sin estrés, y con la altura de la primera vaina, altura de la primera rama lateral, número de ramas laterales por vaina, número de vainas por planta y diámetro del tallo, en condiciones de estrés hídrico. Del análisis secuencial se dedujo que el peso de 1.000 semillas (TSW) y la longitud de tallo principal son los caracteres que más influ...

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Rapeseed (Brassica napus L.) is regarded as one of the most important oilseed crops worldwide. An experiment was conducted to quantitatively examine the genetic parameters of oil yield, seed yield, and yield components for rapeseed by using a half diallel of nine rapeseed cultivars. The 36 F1 hybrids, their parents, and four other commercial varieties were planted in breeding nurseries in 2008 and 2009. During the growing season, the number of pods per plant (NPP), number of seeds per pod (NSP), pod length (PL), 1000 seed weight (SW), harvest index (HI), seed yield (SY), oil percent (OP), and oil yield (OY) were measured. The data were analyzed with the additive main effects and multiplicative interaction (AMMI) model and its biplots. The first two principal components (IPC1 and IPC2) were used to create a two‐dimensional biplot. IPC1 accounted for 28.7% (SW in 2008) to 48.9% (OP in 2009) of the sum of squares of the male by female (M × F) interaction, while IPC2 accounted for 18.3% (PL in 2009) to 31.6% (number of seeds per pod in 2008) of the sum of squares of the M × F interaction. Two heterotic groups were identified for OY, and six between‐group crosses, that is, [Talaye, Modena, Opera] × [Fornax, Orient], would provide maximum heterosis for this trait. The AMMI analysis with the half diallel method identified not only the general combining ability (GCA) and specific combining ability (SCA) effects but also the F1 crosses whose offspring may display heterosis in their offspring. The results can be used to design efficient breeding strategies in rapeseed.

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