Citrus are heavy feeders, requiring more nutrition than most trees.  Not only are the tree's new leaves pure yellow, many of the older more mature leaves throughout the tree are also showing to be deficient., Grow your tree as you wish, but my suggestion is to feed the tree with conventional fertilizes.  Looking at your pictures, it is easy to determine that the tree is suffering from a drastic deficiency of nitrogen, and probably a few  other elements. You don't say how old the tree is.  A 1 year old citrus tree should be fertilized 6 times /year; a 2 year old tree 5 times /year; a 3 year old tree 4 times and a 5 year old tree and older 3 times a year.  I would suggest that you purchase a conventional fertilizer with a formula such as 8-8-8 and fertilize the tree, covering the entire area of the tree's root zone once ever two months during the growing season.   Your tree is so badly undernourished you might even give it a urea foliar spray.  Good luck to you and thls tree,

I agree 100% with Brian, Rangpur is a really awfal fruit.

Harana, the leaf symptom showing a deficiency of iron is:  NEW leaves with GREEN veins on otherwise yellow leaf.  NO wide green  border  around the vein.  NOTE: Iron deficiency often caused by high pH rather than shortage of actual mineral.

If a tree is deficient in iron, then it is proper to apply iron in order to cure the deficiency.  Just as one should not give medicine to a patient that is not sick, one should not apply fertilizer if it is not needed. Supplying iron, or anything, if it is not required is not a good idea.  Harana's trees are 2 years old.  Therefore, the recommendation for a 2 year old citrus tree is 5-LBS. of actual nitrogen per year, applied over 5 applications. The amount of fertilizer applied per each application depends on the analysis of the fertilizer. If Harana purchases a bag of 8-8-8  the solution would be: divide pounds actual nitrogen required by the tree per year (5-lb.)  by % nitrogen of the fertilizer used.   For Harana's  two year old citrus tree   SOLUTION: 5/.08 = 6.2-lbs. divided by the 5 applications, or 1.2-lbs.per each application.

All in all the citrus in the last picture just looks under fertilized, as shown by the yellow/orange veins in the leaf center with some green out on the far sides (symptom for nitrogen deficiency).  The medium that the tree is growing in looks to be OK for adequate drainage and root zone oxygen availability.  Foliage Pro is a good  citrus  fertilizer, although expensive. Citrus are heavy feeders, therefore require more nutrition than most plants.   Organic fertilizers are OK, if there are ample microorganisms present to breakdown an organic fertilizer into a  form usable by the tree.  There is no where near enough microorganisms in container culture to accomplish this. Therefore, an organic fertilizer is not recommended in container culture.  The trees in the first picture shows that they are now growing in containers that are too small for the tree's size.   When a tree's root system  has  filled out all of the available container space, its growth becomes straight up, like toothpaste squeezed our of the tube.  Theses trees also show that they now have or have had an insect problem, probably mites.  They also need more nutrition. Welcome to the forum, happy to have you as a member. The best to you and your trees.

Btian, like I always say...."Good things come to those who wait".

Years back Citrus Joe gave me a young seedling that had twin thorns.  I can't remember the name of the variety.  I no longer have it.  If I  remember correctly, it was an Australian cultivar.

Great post Citrange.

I remember J.Rozier from the original old forum,   Nasnaran being the size of a US quarter, and having 16 seeds must not have much in the way of something to eat.

Bigsnook,  your tree does look better.  You don't need to apply any more Epsom salts at this time.  You could apply additional applications ever couple months.  Good look to you and this tree.

I notice that most all of the tree's fruit production is limited to the bottom section of the tree, with very little production in the higher portion.  Also the tree seems to be very dense and compact with little sun able to enter into the center of the tree.   If It was my tree I would cut out the thick rapid, elongated, growing branches.  Most  likely water spouts.

Yprgps. I know exactly the problem of dry pummelos that, you write about.  I too had the same problem.  I then started a more frequent watering program and also mulched the tree's root zone.  Since doing this regimen I have never again had a dry pummelo  -  not one.