The Application of Ooubled Haploid Plants to Population ... - MSpace
The Application of Ooubled Haploid Plants to Population ... - MSpace
The Application of Ooubled Haploid Plants to Population ... - MSpace
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DISCUSSION<br />
lntercrossing DH lines in B. tapa through the produdion <strong>of</strong> composite<br />
populations led <strong>to</strong> the recwery <strong>of</strong> population petformance for some traits. <strong>The</strong>re were<br />
improvements in seedling emergence, height, seed yield and HI <strong>of</strong> the C, and C,<br />
populations <strong>of</strong> both Reward and DSCJ above that exptessed by the mean <strong>of</strong> the OH<br />
Iines (Table 4.1 and 4.2). In Reward. C, and C, population performance was similar <strong>to</strong><br />
the original Reward donor population wïth the exception <strong>of</strong> increased seedling<br />
emergence and days <strong>to</strong> maturity in al1 C,populations, as well as higher seed yield <strong>of</strong> Cl.<br />
, and C , C, C2,,, and C, at Cannan. In Reward, interpollination <strong>of</strong> 8 DH fines<br />
(Cl,)<br />
resulted in a population with agronomic performance better than any <strong>of</strong> the<br />
individual DH lines and better than the original Reward donor population at one<br />
location, Caman. <strong>The</strong>re was no consistent ranknig between the DSC-3 C, or C,<br />
populations in yield performance or HI. <strong>The</strong> DSC-3 C, generation showed<br />
improvement in agronomic parameters in cornpanson <strong>to</strong> the mean <strong>of</strong> the OH lines.<br />
<strong>The</strong> Cl, and CZ4 Reward composite populations were significantly lower in seed<br />
yield than the C,<br />
Cl.1z and C, and C2,,,populations respectively. Genetic<br />
characterization using randomly amplified polyrnorphic DNA (RAPD) analysis showed<br />
that the 4 DH lines chosen for the C,<br />
population had collectively less heterogeneity<br />
than C,, CG,, and Con (Friesen, 1997). This CM population may not have had<br />
enough variability <strong>to</strong> avoid mating between close relatives and inbreeding depression.<br />
<strong>The</strong> Reward C, populations had higher seedling emergence than their Cl