Pod shatter resistance of rapeseed is of great importance for modem farming practice. In order to determine the combining ability of elite inbred lines and the breeding potential of rapeseed hybrids in terms of pod sh...Pod shatter resistance of rapeseed is of great importance for modem farming practice. In order to determine the combining ability of elite inbred lines and the breeding potential of rapeseed hybrids in terms of pod shatter resistance, analysis of a 6×6 incomplete diallel cross was conducted at two locations. Results showed that a significant variation existed among breeding lines and their F1 hybrids for pod shatter resistant index （SRI）, pod length and width. Pod shatter resistance was significantly positively correlated with pod length. The general combining ability （GCA） effects （GCA=l.58） played a more important role than specific combining ability （SCA） effects （SCA=0.20） for pod shatter trait. The elite lines R1, 1019B and 1055B displayed significant positive GCA effects for pod shatter resistance. Four crosses （1019B×R1, 1015B×R1, 6098B×R1, and 8908B×R1） with high mean performance and positive SCA effects were recommended for developing new hybrids for mechanical harvest in the middle reaches of the Yangtze River.展开更多
Paclobutrazol was sprayed at 0, 150, and 300 mg L-1 during the closed canopy stage and the early bud stage with two high-yielding cultivars of rapeseed, Yangguang 2009 and Fengyou 520. The impact of paclobutrazol on t...Paclobutrazol was sprayed at 0, 150, and 300 mg L-1 during the closed canopy stage and the early bud stage with two high-yielding cultivars of rapeseed, Yangguang 2009 and Fengyou 520. The impact of paclobutrazol on the accumulation and distribution of biomass and its relationship with yield, resistance to lodging and pod shattering were determined. All the treatments increased the resistance as well as yield. The maximum yield was obtained when paclobutrazol was applied during the closed canopy stage at 150 mg L-1. The plant＇s resistance to both lodging and pod shattering was the maximum when paclobutrazol was applied during the early bud stage at 300 mg L-1. Paclobutrazol also delayed senescence, with the higher concentration or later spraying leading to more obvious effects; improved the net assimilation rate before the early bud stage; and promoted the relative growth rate of the main growth organ at each stage of growth and maximized the rate and quantities of biomass accumulation. However, at the higher concentration and later spraying, the increments were smaller. The spraying also increased the rates of biomass allocation to roots, leaves, and pods, but the rate of allocation to stems decreased as the plants grew shorter. The higher allocation to roots and the lower allocation to stems favoured resistance to both lodging and pod shattering whereas higher allocation to leaves and pods favoured yield. The higher concentration or late spraying led to excessive biomass being allocated to roots, which decreased leaf biomass during the bud stage, leading to greater resistance but lower yields.展开更多
基金supported by the National Basic Research Program of China (973 Program, 2011CB109302)the National High-Tech R&D Program of China (863 Program,2011AA10A104)the earmarked fund for China Agriculture Research System (CARS-13)
文摘Pod shatter resistance of rapeseed is of great importance for modem farming practice. In order to determine the combining ability of elite inbred lines and the breeding potential of rapeseed hybrids in terms of pod shatter resistance, analysis of a 6×6 incomplete diallel cross was conducted at two locations. Results showed that a significant variation existed among breeding lines and their F1 hybrids for pod shatter resistant index （SRI）, pod length and width. Pod shatter resistance was significantly positively correlated with pod length. The general combining ability （GCA） effects （GCA=l.58） played a more important role than specific combining ability （SCA） effects （SCA=0.20） for pod shatter trait. The elite lines R1, 1019B and 1055B displayed significant positive GCA effects for pod shatter resistance. Four crosses （1019B×R1, 1015B×R1, 6098B×R1, and 8908B×R1） with high mean performance and positive SCA effects were recommended for developing new hybrids for mechanical harvest in the middle reaches of the Yangtze River.
基金funded by the National Key Technology Research and Development Program of China(2014BAD11B03)the earmarked fund for the China Agricultural Research System(CARS-13)the Fundamental Research Funds for the Central Universities of China(2013PY001)
文摘Paclobutrazol was sprayed at 0, 150, and 300 mg L-1 during the closed canopy stage and the early bud stage with two high-yielding cultivars of rapeseed, Yangguang 2009 and Fengyou 520. The impact of paclobutrazol on the accumulation and distribution of biomass and its relationship with yield, resistance to lodging and pod shattering were determined. All the treatments increased the resistance as well as yield. The maximum yield was obtained when paclobutrazol was applied during the closed canopy stage at 150 mg L-1. The plant＇s resistance to both lodging and pod shattering was the maximum when paclobutrazol was applied during the early bud stage at 300 mg L-1. Paclobutrazol also delayed senescence, with the higher concentration or later spraying leading to more obvious effects; improved the net assimilation rate before the early bud stage; and promoted the relative growth rate of the main growth organ at each stage of growth and maximized the rate and quantities of biomass accumulation. However, at the higher concentration and later spraying, the increments were smaller. The spraying also increased the rates of biomass allocation to roots, leaves, and pods, but the rate of allocation to stems decreased as the plants grew shorter. The higher allocation to roots and the lower allocation to stems favoured resistance to both lodging and pod shattering whereas higher allocation to leaves and pods favoured yield. The higher concentration or late spraying led to excessive biomass being allocated to roots, which decreased leaf biomass during the bud stage, leading to greater resistance but lower yields.
