Mass selection for small‐sized cysts in A rtemia franciscana produced in V inh C hau salt ponds, V ietnam

Unidirectional mass truncation selection for small‐sized cysts was carried out on brine shrimp ( Artemia franciscana Kellogg 1906), Vinh Chau strain, Vietnam, through cyst sieving and then culturing the selected individuals (<5% of the population) under field and laboratory conditions over two successive generations (F 1 and F 2 ). The results showed that at both culture scales, the cyst size of the selected line was smaller ( P  < 0.05) compared with the control (non‐selected) line, illustrating that there was a response to selection. The cyst size decreased about 3% per generation and the accumulated gain on the target trait was in the range 5.82–6.07% at the end of the selection process compared with the base population. The realized heritability estimation (h 2 ) for cyst size was 0.23 ± 0.06 and 0.74 ± 0.19 in the field trials and 0.34 and 0.51 in the laboratory test for the F 1 and F 2 generation respectively. The variations found between the respective trials may be explained as the result of environmental interaction with the selection process, but the results show that a selection program for small‐sized cysts in A rtemia by mass selection is possible.