Breeding Heat Tolerant Abutilon

Abutilon xhybridum, a member of Malvaceae, has gained popularity in the southeastern United States as a spring and fall flowering herbaceous plant. To further breeding Abutilon with heat tolerance and diversified flowers, ten cultivars were selected, propagated, and grown in the greenhouse for artificial hybridization. Stem cuttings of Abutilon rooted easily with aid of 1000 mg·L^-1 K-IBA in about two weeks. All transplanted cuttings reached full bloom in about two months. Although we did all reciprocal crosses among all ten cultivars, only A08-1603 (pure yellow, light bloom), A08-1607 (yellow with red throat, heavy to medium bloom), and A08-2112 (red, heavy bloom) set fruit and yielded seeds. A08-1607 was selected as a parent since it shows good heat tolerance and continual blooming through the summer and fall months. A08-1607 X A08-2112 had 41.7% fruit set and produced 7 seeds per fruit. The cross, A08-1603 X A08-2112, set 25.5% fruits and 14 seeds per fruit. If crossing A08-2112 (female) with A08-1607 (male), only one out of 43 crosses set fruit with a yield of only 3 seeds. The low percentage of successful crosses and limited fruit set might be due to incompatibility and higher temperatures in the greenhouse. Further studies should focus seed germination and evaluation of new germplasm. The mechanism of cross-incompatibility should also be investigated.