New early navel oranges

Dr Dave Monks and Andrew Creek

In the last few years, several new, early Navelina orange sports with maturity four to six weeks earlier than standard Washington navel have been evaluated in Australia. The juice results at maturity are in Table 1.

Leng, Pasin and Newhall navel oranges are all considered early navels, however Navelina clones and the more recent sports are the earliest maturing.

Now Australian citrus growers seeking early fruit can choose from Navelina, M7, FJ Navel and Rayno (Figure 1). These varieties are available through Auscitrus or specific variety managers.

Navelina 7.5 from Spain is the Navelina clone mostly planted in Australia. Fruit shape is variable though more oval than Washington Navel. A rounder Navelina 315 clone from Italy is planted less as its fruit size is considerably smaller. When picked at maturity, Navelina is a great eating piece of fruit. Many growers will say their favourite eating orange is a Navelina that missed picking, suggesting full flavour develops after acceptable BrimA benchmarks are met.

M7 is an early navel with high Brix, good acid and juice that was found as a limb sport in Kenley, Victoria. M7 reaches full colour in the second week of May (Figure 2). Growers have expressed some management issues that require overcoming, specifically variable size and basal splitting:

“I’ve been picking my M7 for 3 years now. I am happy with the way they colour at least two weeks earlier than my Navelina. A very sweet and juicy piece of fruit that is much rounder than the Navelina. I must follow a program strictly to prevent splitting. I also found my trees needed more copper to prevent deficiency. Yields have been lower for me, however, when I speak to other growers from different regions and their yield is fine. Maybe the citrange stock is not the best for my soil“. Frank Battistel – Griffith.

“Seven years ago, we decided to go with some M7 as it has superior eating quality: not only earlier but as a navel period! The first trees we had experience with were topworked over from Thompson navel on both citrange and rough lemon stock (trees were 30 years old in good health). So far, we have been harvesting M7 off these topworks for five seasons but are still a long way off full production. External fruit quality has been a mixed bag, with small fruit one season to very large rough fruit the next. Splitting has also been an issue when the fruit is larger. If the fruit is left until full colour or later we have found the fruit to still be in very good condition. Internal quality has always been excellent but trying to achieve an acceptable packout has so far eluded us with lots of blemishes and unfavourable size ranges. Maybe this is due to young trees? Also, we planted young trees on citrange six years ago in a different area that is more protected from the wind and we have had a lot of issues with incompatibility, producing dwarf trees and lots of suckering (about 10 – 15 % of the orchard). For the last three seasons we have been using the M7 growing protocol with more copper, heavy pruning and GA crop manipulation, but we have still not cracked the code to produce over 55% class one, nice sized fruit. I have witnessed other trees planted before ours that seem to produce more consistent crops of nice fruit and their trees look more uniform as well. Most people I speak with are trying very hard to make this variety work as its timing and eating quality fit so well into our markets. Hopefully success is just around the corner?” David Steven – Ellerslie.

FJ is a good quality early navel that was found as a limb mutation in Leeton, NSW. FJ reaches full colour in the fourth week of May. It has good Brix, acid and juice. FJ is round, has a consistent yield and the fruit are of good size. A grower visiting the Dareton evaluation site recently commented that FJ ‘just fits in with our usual farm practices’, compared with M7 which required special attention.

“I’ve been picking 250 trees of FJ Navel for 5 years now. FJ is a nice piece of fruit that packs rounder than my Navelinas. The FJ colours naturally better and quicker than Navelina. Internally the fruit is sweet and juicy.” Mick Cuzzillo – Stanbridge.

Rayno is a good quality early Navelina sport from South Africa. Rayno reaches full colour in the fourth week of May. It has good Brix, acid and juice. Rayno has a neck and most fruit are oblong, but one packer/grower said he did not mind the shape and thought he could find a market for it. Rayno has produced a high yield of mid–small fruit in the first two years of production from topworked trees. It is too early to give a fair impression of the fruit size, but we will follow it through next season.

Rootstock incompatibility is an important factor to consider with Navelina and these Navelina sports. Since the initial plantings in the 1990s, Navelina has been incompatible with Swingle Citrumelo and C35 citrange. Navalina planted on C35 roostock began to die from about 15 years of age at the Loxton Research Centre (Gallasch and Skewes). Carrizo citrange has also shown some incompatibility symptoms and a sweet orange interstock is recommended for a long-lived tree.

Table 1. Juice results at harvest maturity 2019.

Figure 1. From left to right: M7, Rayno and FJ mid-May.

Figure 2. The harvest window for the varieties.