As a result of phenological observations, it was found that the phenological phase duration in various melon varieties and hybrids in the nursery collection differed. Female flowers appeared on the melon plants after the appearance of men flowers. On the average from 2012 to 2014, the period from germination to the first female flower appearance in the hybrid nursery collection was 44-46 days. The hybrids under study were divided according to the period from germination to first-fruit ripening into two groups: middle-early and mid-season hybrids. The following varieties were classified as the middle-early: Pasport (control 1), Super star F₁, Goldi T3 F₁. Their vegetation periods were 79, 80, 79 days respectively. The mid-season hybrids were Spokusa F₁ (81 days), Gurmet F₁ (82 days), Karamel KL F₁ (81 days) and Amal F₁ (81 days).

According to the period from germination to first-fruit ripening, in the mid-season varieties there was singled out a variety with the shortest period, which was 2 days less than in the control. This was an ultra early ripening variety Zabavka, which was bred at Dnepropetrovsk research station. Its vegetation period was 73 days. The longest vegetation period was in the varieties Lypneva and Fortuna – 80 days, and it depended on the genetic features of the varieties.

The vegetation period in the mid-season varieties was from 82 (the variety Zlata) to 86 days (the variety Beregynia). However, this index was almost at the same level in the varieties Ineyia (83) and Lada (85 days) compared to the control variety Samarska (84 days).

The fruit yield in the melon varieties and hybrids in the nursery collection changed during a three-year period. The lowest yield in the hybrids was recorded in the variety Super star F₁ in 2012 – 14.7 t/ha and 14.8 t/ha in 2014. The highest yield was observed in the hybrid Amal F_1, and it was 21.8 t/ha in 2013. Moreover, the favorable weather conditions contributed to the plant growth, which led to the significant yield increase in all the varieties during 2013 compared to other years.

On the average during the three-year study period, the following hybrids showed significantly higher yield capacity: Spokusa F₁ – 20.4 t/ha, Amal F₁ – 21.3 t/ha and Goldi F₁ – 20.9 t/ha. These hybrids exceeded the control hybrid Pasport F₁ by 3.5; 4.4 and 4 t/ha respectively.

From 2012 to 2014, the yield capacity in the middle-early melon varieties ranged from 14.9 t/ha (the variety Zabavka, 2014) to 24.2 t/ha (the variety Fortuna, 2013). This index was significantly higher than in the control 2 variety Titovka in such varieties as Lypneva (by 1 t/ha), Fortuna (by 4 t/ha), Didona (by 1.9 t/ha), Krynychanka ( by 2.1 t/ha).

The significantly lower yield capacity was shown by the variety Zabavka – 3.2 t/ha less, with the lowest standard fruit weight.

In the mid-season varieties, the highest fruit yield was recorded in the variety Beregynia (26.6 t/ha), while in the control variety Samarska the yield was 3.1 t/ha less, and it was 23,5 t/ha. This index was significantly lower in the variety Ineyia –
5.9 t/ha less, and it was 17.6 t/ha. The variety Ineyia formed the smallest fruit, which resulted in the lowest yield capacity.

The Lewis index shows environmental adaptability of different melon varieties in the collection material. It indicates how a heterotic hybrid or variety adapts to the growing conditions. The best adapted varieties to the growing conditions of Forest-Steppe zone were: the hybrids – Gurmet F₁, Karamel KL F₁, Goldi F₁; the varieties Lypneva, Chaika, Lada, Zlata. In the three controls (Pasport F₁, Titovka and Samarska), the variety Samarska was the least adapted.

On the average from 2012 to 2014 the research showed that the standard fruit weight in the middle-early varieties was the highest in the variety Fortuna – 1.5 kg, by 0.3 kg more than in the control variety 2 Titovka, where fruits were 1.3 kg.
The smallest fruit size was formed by the melon variety Zabavka – 0.9 kg. The average value of this index (1.3 kg) was observed in the varieties Lypneva, Didona, Golianka, Krynychanka.

In the mid-season varieties, the largest standard fruit weight was recorded in the variety Bereginia bred by Dnipropetrovsk research station, in which this index was 1.7 kg. Small fruit size was recorded in the melon variety Ineyia (1.2 kg), Zlata and Lada (1.3 kg), while in control 3 Samarska their weight reached 1.5 kg the average. However, it should be noted that due to the optimal weather conditions, which were in 2013, the standard fruit weight in the variety Bereginia was 1.8 kg, which was more than in control variant by almost 300 g.

Key words: melon, adaptation, variety, hybrid, field conditions, yield capacity, average fruit weight.